I would agree JD is probably a perceiver of some kind. I would say either ENFP or INFP. He doesn't seem to be as firm on his decisions as most Js are. In fact, usually I've noticed when he wants to be decisive about something he has to really put his mind to it. I think for most Js that kind of thing would come more naturally. He's probably more of an extrovert, although if he is he's not tremendously extroverted. Even though INFJs have dream worlds too, JD's dream world screams NFP to me.
As far as Dr. Cox, he is definitely in my mind an NTJ, without question. Whether he is introverted or extroverted is kind of a toss-up. Even though the classic antagonist is often ENTJ, sometimes Cox's behavior might be a mechanism to want to be alone by pushing others away. But other times it just seems to be a means to control other people.
BTW: Scrubs is on as I type this.
A hero is someone who does the right thing without expectation of reward, just because it's the right thing to do.
JD = INFP (close to the E/I border)
Turk = ESFP
Cox = ENTP/ENTJ (I could have said ESTP as well if it weren't for certain moments of clear N and his distaste for the ESTPish surgeons.)
Jordan = INTJ/ENTJ/possibly ISTJ or ISTP, but less likely
Elliot = Neurotic ISFP/INFP (Definitely Fi and she's way too unstructured in her head to be a J. The OC tendencies seems more like a result of neuroticism, and she's far too random about what she's OC about to be a J.)
Janitor = ISTP (maybe INTP)
Carla = ENFJ/ESFJ
Kelso = ESTJ
Lawyer = ISFP
I think this does the trick. Cox doesn't seem to have any Ne or Se, I don't know what ENTJs are all like personally, but he might be one of them.
can anyone do the newer characters? I don't even remember their names... might need to watch some more.