I'm probably not making this decision based on cost - while NYU will still be more expensive even if I get an extra 10K for a PI job 2L summer, there are some possibilities for cheaper living if I go to NYU, namely that my parents may be moving within commuting distance of NYC. I don't particuarly like that option, however - so living situations won't be ideal at NYU, whether I pay $1500 a month to live on campus, less to live elsewhere and commute, or nothing to live with parents and commute.
Although I'd probably live off campus instead of the LC at Michigan, I would probably give the edge to Michigan in the housing category.
Basically at this point, I feel my heart is at Michigan and that my brain is (or should be) at NYU. I think NYU is a slightly better school, and better geared if I want to do public interest and just as good as Michigan if I don't. But I want to live in Ann Arbor and go to Michigan football games and walk across the law quad, and all that sort of stuff.