I dont think many INFJs will like roommate situations too much because having a roommate requires you to compromise a lot (like with listening to music, especially if they dont have the same musical taste as you) and even a good friend may have small quirks which annoy you. I once had this INTP roommate and while I was cool with him he would constantly snort -- so if I wanted to know if he was home I would listen to that sound -- either that or the sonar ping his blackberry made everytime he recieved a message (which was approximately about 30 times a day). I don't know why but I gradually developed somewhat a distaste for those habits, even though I still liked the guy.
Generally its difficult to find a roommate which makes living with one as good as living alone. The good thing about the aforementioned INTP living with me was that he was a gamer, was *sort* of into geeky stuff, and generally was an N so we could talk about N stuff sometimes. Other than that we were far different people -- and I probably wouldnt have been able to tolerate the situation if he wasn't a good hearted kind of guy.
So yeah it tends to be pretty good living alone.