I've posted this in a number of other places, but I think that UChicago's conservatism is way overblown, simply because conservatism is represented and considered as opposed to being summarily dismissed, as is the case with much of the rest of the T14 (UVA being another notable exception).
I attended a discussion panel on peace prospects in the middle east last summer with 3 panelists who were supposed to represent a conservative viewpoint, a liberal one, and one in the middle of the road. The "centrist" and the leftist ended up ganging up on the conservative (as a left-leaning centrist who finds agreement with both parties on different issues, I try my best to view these things objectively). You will not feel any less accepted on the far left of the spectrum than on the far right - but as intellectual as the place is, you'd better be willing to defend views on the left as opposed to assuming they'll be accepted without justification, as you may be able to do at some other top schools.
I think of UChicago as more intellectual, and NU/UVA as more pre-professional (I did attend UVA undergrad, but don't know a ton about NU). Anyone care to elaborate/disagree?