Thanks for all the input guys. A lot of your descriptions really resonate with my situation.
To flesh out the details a bit more....
At work I am the only NF in a team of 3 hardcore SJs. Well, there is actually an SP on our team, but he has been pretty much completely isolated by the SJs who consider him lazy and useless and make their disdain for him quite clear. I will say that the SP is on the lazy side, but I also think the way the others have isolated him is extreme and just makes our entire team dynamic toxic. From what I've heard they are working on getting him fired. In a way I feel bad for him, in a way I think he brought it on himself, and in a way I'm relieved that it's him they're gunning for and not me. Having just joined this job in the last 9 months, I am trying to mind my own business, do a good job on my work, and keep this job in such a tough economy!
Anyway, the other two SJs (an ESFJ and an ESTJ) I get along fine with, in fact one I am even pretty good friends with outside of work. They seem to regard me as different from themselves but respect that I am a hard worker and let me do my thing with minimal conflict.
The ISTJ on my team though really seems to have it out for me lately. I think she has lost respect for me because in some areas I am not willing to go above and beyond like she and the other SJs do. Now, let me say that I am a very hard worker. It's actually been very strange starting this new job this year because in almost every other team I've ever been a part of, I'm usually the most type-A, hardest working team member. But then again I've never been on a team of hardcore SJs before lol ;o)
So anyway, this year I'm working harder than I've ever worked before, putting in a solid 55-60 hours per week, but as an NF I put a lot of value on work-life balance, and so there's a certain point in the work load when I'm like I need to shelve this, go home and relax, and start fresh tomorrow. And so I don't go volunteering for extra work like the others (especially the ISTJ) are apt to do. If a teammate specifically comes to me and asks me to complete an extra task, I'll do it and I'll do a good job, but it's just not something I am going to volunteer for unasked when I already feel that I'm working too many hours. I don't want to burn out, I don't want to start to hate my job, I don't want to become an unhappy person, so I am selective about what additional duties I take on beyond my basic duties, which as I mentioned I work very hard at and do a thorough job on.
The ESFJ and ESTJ don't seem to have a problem with me for this, but the ISTJ, to put it in the words of an earlier poster, appears to have lost respect for me. She works 24-7 and seems to think that I should be willing to do so as well. She has always been one to make digs and sarcastic comments after a person speaks, and it always bothered me a little but I used to just brush it off and not worry about it. In the last week however, things have reached a boiling point. The comments have become more pointed and more rude (snippy little remarks, often spoken under her breath or to another teammate, about how I'm not doing my job right or about how what I'm saying is incorrect). I feel she's disrespecting me but I'm unsure what to do. As a new employee I have limited power within the organization, and I don't want to end up alienated like the SP has been. My husband thinks I should confront her, but I'm not a very confrontational person, and the ISTJ has a very sharp tongue and can be quite defensive so I just don't picture a confrontation going well. I usually get along easily with people, and most people have a strong respect for my work ethic and job performance, so I don't have much experience with these kinds of conflicts.
In the past when someone is rude or mean or disrespectful to me like she has been, I resort to the old INFJ doorslam trick that is often referenced on this forum, and that usually serves me well. I've been mulling that over -- being polite but cool to her and uber-professional but having nothing to do with her outside of work-related interactions. (No more going to each others' get-togethers, celebrating each others' birthdays, writing on each others' Facebook walls, etc., etc.) In the past when I've done a doorslam it's been very effective and the offending party gets the point loud and clear that I am done with them because of their behavior towards me. But the tricky thing is that the ISTJ is actually slated to be team leader next year. She's pretty passive-aggressive, and when I go to doorslam mode I'm pretty passive-aggressive, and I don't think a passive-aggressive battle of wills would necessarily end very well for me if she's in a supervisory position over me. <Sigh.>
Anyway, sorry to write so much. I'm bummed that this situation is bothering me to the degree it is (darn NF sensitivity). But anyway, I do appreciate y'all's comments and ideas on the matter.