Actually, the Olin Hall part is a good point that I meant to make earlier -- not to insult anyone who was thinking of living there, but I think a certain type is attracted to living there (I can understand 1st year, but really, 3rd and 4th years?!). I also felt a little more comfortable talking to some of the non-Olin people -- they seemed more like the people I would be friends with outside of class, etc. It seems like if you live in the dorm, you would be a little more in the "WashU bubble" and I just don't think that bubble would be for me, all day every day. Plus, with the cost of living around there, why not get a great apartment nearby and take more advantage of the city, and other parts of the school.
On a slightly unrelated note (I have a tendency to go off on tangents), one thing that was initially pretty important to me at the beginning of this process was that I really wanted to find a school that had lots of other grad programs (ie, law school, bus. school, etc.) so that I would have a chance to interact outside of the med school and the med students. However, I've found that most med schools I look at tend to isolate themselves from the rest of the university pretty well. Anyone else notice that, and if so, does that bother you?