Alright, I actually had to sign up to the forum so I could reply to this, it's probably stupidly old by now but that's fine.
First off, wanted to say thanks for the post since it actually did provide a great deal of information and helped me with choosing a career for my own self. So yay to that!
Secondly, or lastly? Well probably secondly, I doubt I'll maintain attention span long enough for this to be the end of it... oh well, anyways! Secondly(ish): I'd also like to note that with a bit of careful though on the matter, I've come up with a slightly modified rule that I used myself.
Due to the ENTP's standard inability to sit still on a single topic for very long, it helps to pick a basic field of study/work to focus on, especially one which can lead to constant changes.
For example, I myself ended up going with 3D game art design, but primarily, this has several branching effects which's whot makes it so useful. If I had to do the same thing EVERY DAY for YEARS, well I'd go insane. If it weren't too late already that is... but anyways, the point is that I can start off with level design, move to character design, and then these branch out further as well; character design can split into several categories from just the animation aspects of a model already made, to creating a character's personality, dialogue, appearance and so on, while level design can also branch off into things such as actual level layout, to enemy design, bosses, from how a boss looks and moves, to whot kind of methods they employ in offensive and defensive, relating to how one needs to combat them. In the mindset of a MMORPG for example, this can mean an immense number of things to cover, even stuff like special effects like explosions or spells, to a gradual move from graphics design to balance, AI design, and so on. Chances are, 30-40 years from now I could still be in the same field yet covering completely different tasks every year. Toss in that every game itself is different, especially with newer technology and such being added constantly... I mean they now use 3d instead of 2d, dvd's instead of cartridges, in the past 20-30 years alone the design process has grown incredably to the point that it's unrecognizeable as the same field any longer. This kind of thing is PERFECT for an ENTP.
As such, here's my personal list of things that is required for my own decisions on such:
- multiple fields closely related; need to be able to change when yeu get bored with one
- growing trends; if yeu're stuck doing the same job forever, it had better change and adapt over the years; technology is great for this currently, sciences help but can quickly grow boring due to next part
- less paperwork; I personally find I NEED to spend time DOING stuff, as much as I love writing, noone cares about a 15 page essay that pretends to be a status report. An ENTP may love something like astronomy, but it can quickly grow tiresome with the scientific process, since there's so many rigid rules to follow, in order, documented repeatedly at each step. This quickly turns into mundane repetition and kills the desire to continue, this's the main reason I ended up ditching the particle physicist line of thinking... sure I have some nice theories and stuff I'd LOVE to test... but the reality is I'd grow too bored with it
- Chaos. Seriously, it has to have an element of unpredictability to it, if yeu don't find yeurself having to think on yeur feet, yeu're screwed. I actually enjoyed my time working at a call center for cable tv repair, because every call was completely different. Even a 'typical' call could quickly go weird... someone who doesn't listen well, is kind of ...'slow'... or just bizzare circumstances (had one where it was uhm... 'fun' trying to get someone to reprogram a remote via relay across the house... phone downstairs, remote and tv upstairs... 3 people shouting directions given over the phone across the house like some weird echo

). Anything that maintains that there will be something NEW happening every few moments, or at least unexpected to the point of not being able to concieveably prepare for it is for the best.
- Fun. Period. It doesn't matter how much monies it pays, if yeu HATE doing it, then wth are yeu doing it for? Yeu work TO live, not live to work, per sam starfall. If yeu HATE yeur work, yeu're going to be grumpy when yeu get home, and it'll just keep adding over and over until yeu flat out don't care and get pissy about every little thing. Living yeur life that way won't work. It has to be something yeu enjoy doing. Note that it's WORK though. This won't be perfect; if it were fun 100% of the time they'd charge yeu to do it, not pay yeu, so there has to be some aspect which's annoying enough that it sucks, but it doesn't mean yeu should be willing to accept something that's 100% suck instead of 20% suck. Go with something yeu like doing. As an ENTP yeu're good at pretty much everything anyway, so it's not like yeu can't get into the business whotever it is.
- Creativity. ENTP's are known especially for their desire to 'make' something, though this's actually a misnomer I believe... it's not the "MAKING" part that's important, so much as the showing it off part... specifically, making a pretty vase from pottery's useless unless that vase can be given to a customer who appreciates it and finds enjoyment in it. As a whole we like to show off indirectly, and love to affect others positively, or bend them to our way of thinking. Earlier in this very thread, someone posted they tried teaching because they wanted to be able to have an impact on kid's lives, and let them learn... this's our ultimate goal, whether we realize it or not, is to be able to get people to see things from our point of view, or see things how we envison them. A degree of creativity is required for this however; if yeu're stuck in a rigid orderly cycle, then this ability is cramped and can't be let loose. For the previous example, the school board has rules which mean yeu HAVE to teach certain things every. Single. Year. Over and over and over. Yeu HAVE to ask certain questions on tests, yeu HAVE to proove yeu've taught the kids certain required things, and yeu HAVE to follow alot of strict rules to make sure that the learning is more or less evenly distributed... yeu don't want to have a case where kids who take two courses (say math 10) where it's 50/50 which teacher they get... if they get the 'good' teacher, they'll learn far more by default, if they get the 'bad' teacher they won't learn a thing. They go quite far out of their way to prevent this, to the point of actually restricting the good teachers to make it so it's not so imbalanced, as dumb as that is. This's another reason why I avoided the physics thing... only real jobs available are teaching classes, and I know I couldn't do that.
- Freedom. Seriously, if yeu lock an ENTP in with strict rules, and don't let them do it their way, they're just going to find a way to bend the rules or just flat out ignore them anyway. In many jobs this will eventually just lead to getting fired, or high tensions with management. The ONLY reason I didn't get fired from my call center work was because I was way too good at whot I did and they couldn't afford to ditch me, despite that I completely ignored half their arbitrary rules, going with the spirit of the law, rather than the letter of the law, and perverting the letter of it to fit the spirit. This annoyed management to no end, and as the client kept getting more and more restrictive, eventually I would've been fired had it not been for medical issues which forced me to leave early (not being able to speak at all for about 6 months kind of kills ones' ability to talk on a phone for some reason, go figure). The point, is that if yeu don't have freedom to do things yeur way, it's going to piss yeu off to no end, and yeu're just going to do it yeur way in the end anyways, because let's be truthful with ourselves here... we don't handle rules well. Especially restrictive ones. We get more and more annoyed at being restricted in our options until eventually it just snaps and we don't care anymore and do it our way anyways. Tell an artist they're only allowed to paint with the colour grey, they'll find all sorts of ways to use multiple greys to make sketches and nighttime scenes, get annoyed at them for that and restrict it more and more until they're not allowed to do anything but show a blank canvas and are not allowed to use any material at all to affect it, and they'll start clawing at it with their nails to leave imprints. Restrict them from touching it and they'll stop caring and go back to just drawing as they please. Yeu can only restrict people in general so far, but ENTP's, being especially creative and disliking restrictions, are more susceptable than most to this.
- Less order. I know my desk is a mess, I know where stuff is on my desk, it's carefully organized in my own 'organized chaos' mess of things, but to a casual observer it's a nightmare. They'll have to live with that. If I try to be organized, I loose things, and will end up wasting far more time and effort on trying to make things look tidy, and most of the time will cut corners, shoving papers into a drawer or whotever. Give me paperwork to do, and I'll take every opportunity to expand my answers... I don't like neat, tidy 'orderly' yes/no questions... the questions can be listed in such a way that the individual questions, or those as a whole, can lack severe amounts of highly important information. I had an optional survey I did once that was all yes/no questions, and by the end of it I was just in awe at how poorly it was set up... my answers ended up making me sound like a pedophile by the end because of how it was organized, with no margin for explaination or clarification. Order is inherantly bad in that it requires limiting things down to a very specific set of possibilities, there's no possible way to maintain order in 500 open ended questions, yeu need to break it down into careful restrictions. This can be used to good effect sometimes, but mostly those're in cases of suggestive selling and witch hunts a la "do yeu like carrots, or prefer to BURN THE AMERICAN FLAG AND EAT BABIES!?" okei... uhm... I like raw carrots but not cooked ones, ZOMG HERETIC! But yeah, having things be less restrictive and rigidly ordered gives far more capability for an ENTP to carry forth their bizzare ideas... generally they're very good ideas, but difficult to explain, and the individual themself is far more interested in working on the solution than in trying to explain themselves every step of the way. Quick (alright semi quick) personal example; I do math weirdly in my head... ask me whot 11x27 is and I won't be doing it normally at all... instead of writing it out 11x7 + 11x20, it's going to be more like 10x30 (300) +1x30 (30) for 330, then remove 11x3 (33), which's rounded to 330-30, for 300, then -3, so yes the answer is 297, and I can do that in my head faster than someone can write it out traditionally. The problem is, if I write down anything at all, the only thing yeu'll see on my paper is 300, 33, 297, because those're the only numbers I need, the first two just being placeholders so that I can remember where I was. This drives math teachers insane because they have absolutely no clue whot the thought process is, or where those numbers came from, and if I write the whole thing out I'll run out of time because there's many extra steps taken compared to most people, so when I was in high school, I was told on my tests to "show my work" endlessly... problem is, if I showed my work, because of the lengthy procedures, I would run out of time and not finish the test. If I didn't show it, the teacher would get pissy and just mark everything wrong for not showing how I got the answer. It's loose-loose, despite it being more accurate, and faster than the traditional method. This type of problem solving is fairly common to ENTP's I've since realized, though maybe not in that exact way. The general problem though is that ENTP's will usually do things in a very effecient, but roundabout method which's difficult to comprehend, and they hate having to explain themselves while they're busy doing it; ask them AFTER and sure they'd just LOVE to go into detail and show yeu the thought process behind it step by step, as they like showing off and teaching people, but they HATE having to stop in the middle of something they're working on to explain it. I know that I, at least, get more than a little irate when interrupted with questions, since my mind just didn't get properly developed in terms of speech... I can multitask a dozen things at a time easy... but not speaking. It takes all my concentration to try to form sentances due to the mind wandering aimlessly constantly, and the mind comming up with new concepts far faster than the lips can keep up with the speech part of it. As such, this usually turns into just drifting off, loosing my place, and having no clue whot I was talking about mere seconds before very frequently. Or if trying to do anything else at all, having to stop it entirely to answer a simple question as I can't work on the speaking and doing part simultaniously. But while that's a personal example, the concept is true to many other ENTP's... being forced to stop one task temporarily to concentrate on another will often lead to irritation due to often pouring all attention and focus on a single topic. We're very prone to not finishing whot we start, and the largest reason that I've personally seen, is due to interruptions. Anything from being forced to write a status report, to the neccessity to sleep or eat, all detract from a deep level of intense thought. Once yeu've lost that state of epiphany, it's probably gone for good. As such, orderly 'must do everything in an organized method' is a very very very bad thing, as it immediately restricts our strongest aspects of our nature, primarily the ability to work on the fly, and come up with grotesquely creative concepts. Forcing rigid order upon us strangles the biggest advantages we have, which just makes us feel like crap that we're not living up to our potential, and not allowed to do our best work. Unfortunately, we're so rare that most people aren't used to having to deal with this, and those that do, rarely ever learn the problem as we ourselves rarely understand it fully. This generally means that we're dumped into traditional methods of organization and expected to excel, and instead flop about helplessly in the confined little space. Give us the room we need to work, and break away the arbitrary restrictions, and genious can emerge, but add too many chains and the only creativity yeu're going to see is how deftly we manage to break the chains and twist logic against our captor. But then all our energy is focused on breaking free of the rules that bind us that we can't spend that energy on actually DOING the stuff we're supposed to be doing. This defeats the whole purpose... so yeah, make absolutely sure that WHOTEVER job yeu get, that yeu stay AWAY from anything that is heavily restrictive on intense order... status reports, managers that expect things to be done in an exacting procedure, anything of the sort has to be avoided at all costs. Especially if those things are NEEDED. If yeu try to work at something that requires following specific rules TO THE LETTER or else it becomes highly dangerous... well... keep an ENTP way the hell away from that or there's going to be problems, especially if they get bored.
...Is it just me or are each of these getting progressively more ranty with each point added? Huh... I think Imma stop here before I dig myself into a hole XD
Anyways, those're mostly my opinions, take and leave as yeu will ^.^