I always thought ENTP. As with House, the show is modelled after Sherlock Holmes and I think there are parallels between all three characters: brilliant in their field, have learned how to get those they need to work with them even though they break all the rules and don't let others in on what is going on, very private people in many respects, arrogant, have surprising array of unexpected talents, resourceful and innovative, like to do things with a bit of flair, people either love them or hate them but don't feel ambivalent about them, a bit self-destructive and need someone to save them, even while they will use their most loyal friends over and over again... I don't see a lot that strikes me as NFJish about him.

I love the show and I like Jane's character especially (plus he's just nice to look at and has good taste in clothes and cars).