My own experience is that it was easier to integrate with people doing other subjects when I was doing my English degree than it has been doing Medicine. But that might easily be explained by the fact that I've been to two different universities, and/or the fact that I lived in college for two out of three years during my first degree, whereas I didn't live in halls even in my first year of Medicine, so didn't get the chance to meet as many non-medics. I do know a few medics who make a conscious effort to keep their social group as non-medical as possible, so it can be done - but I think it's something they have to work at, whereas it's easy to slip into socialising only with medics.
I think the first poster is right about the reasons for med schools being slightly separate from the rest of the university, by the way. We run on a different timetable to almost everyone else, and the style of the course is also not really replicated in other subjects. Oh, and our lecturers are usually clinical staff, so it pays to have lecture theatres that are located with the hospitals - rather than the main university site - in mind; that might also contribute to the separation, too.