I've been living in cambridge, MA for the past two years, so I can give advice to anyone looking at MIT or Harvard (Not that you need me to convince you to go to those schools)
Honestly, Cambridge is an awesome place, and I wish I could stay here longer. Cost of living is high, unless you are from NYC or California, but you have pretty much anything on hand you could ever want. The city is one of the most walkable places in the country and Cambridge is bountiful with bike lanes (Boston proper not so much). A car can be nice for grocery shopping and weekend trips, but is far from necessary. It gets pretty cold in the winter and we have gotten 70 inches of snow this winter, but that's above average. The weather in New England is also really indecisive. Two days ago it was 20 degrees, today it was almost 50. We got a thunderstorm tonight and I wouldn't be surprised if we got a snowstorm the next week. I've seen it 70 in the beginning of February and I've gotten snow days in March. That said, It's nice in the summer and cold in the winter; you get a nice range of seasons.
I currently live in the Inman Square area, and I'd highly recommend it to anyone looking to live off campus. Both schools are about 15 minutes away and there are busses that go directly to campus for those cold winter nights. It's got a lot going on for it and is relatively cheap (I pay $650 a month which is cheap for the city) There's a ton of great restaurants and jazz clubs out here and you're really close to the center of the city.
Harvard Square tends to be over run by tourists and visitors, but there are a ton of great bars and restaurants. Kendall Square (MIT) tends to be low key, with a lot of business people there during the day and empty at night. I could make a ton of suggestions for all different types of restaurants and music venues, but you probably wouldn't be able to see those during your open house weekends anyways. Suffice it to say, if there is something you want, there are probably two or three places that do a great job in 15 minute radius. (I could answer any specifics, but a decent scouring of yelp should lead you to the same conclusions) If I had one piece of advice for the city, it is don't fall into a rut. Keep trying out new places, there are a million options and one day, after living in the same place for two years, you will find a place you absolutely love and say "why didn't I ever eat here before?"
The one thing I do hate about the city is it is dead at night. A lot of restaurants close early, Liquor stores close at 11, The subway stops at 12 and bars close at 2. Even if you're not into that scene, it sucks if you're visiting friends across town and have to leave at 11:30.
If anyone has any more questions about Cambridge or Boston, I'd love to answer them. I can't speak much to the qualities of either school, but I know the city pretty well. But mostly, I'd love to see more people share opinions of cities and schools that they know, either from going to school there or growing up in the area. (Particularly anyone who knows Tucson, Houston or Rochester

EDIT: I could also give info about the Urbana-Champaign area, I lived there for a summer.
DOUBLE EDIT: Ok, I'm bored and I can only press the refresh button on my inbox so many times before I get insane, so I will share my thoughts and opinions on Urbana-Champaign. I only lived there for three months over the summer, but I know a large number of students there so I think I got a somewhat decent scope of the area.
Chambana is pretty much the definition of a midwestern college town. You're surrounded by cornfields on all sides, but there's a nice city nestled around the university. Most stuff is close enough to walk, and there's a good bus system if you are farther away. A car isn't necessary, but having a friend with one certainly helps. Housing is cheap; you can get away paying about $300 a month for an apartment right around the corner from campus, but a lot of it is of poor quality. Most of the housing market revolves around undergraduates, so if you want a nicer place, you might have to pay more. Either way, don't get a place without seeing it first, lest you wind up in an apartment with concrete walls and a roach infestation.
There's plenty of restaurants and bars. Again, a lot more centered around the undergraduate population, but there are plenty of places you can go and escape the throngs of drunk screaming freshman. (Entry to bars is 19+ in Urbana) If you want great food and even better beer, check out Crane Alley. Also, make sure you go to the Canopy Club on Tuesday nights for piano man. Whatever your interest, it shouldn't be too hard to find a place that will match you.
It's only a couple of hours to Chicago, so you could make trips up there if you had some pressing interest. (You could also drive to St. Louis in a couple of hours too, but why in the world would you do that?) There are shuttle bus services that run from the school to the airport in Chicago.
All in all, a nice middle of the cornfields college town. Probably better suited to undergrads, but still plenty to do for a little bit older crowd. Again, if anyone has any specific questions about Chambana, I'd be glad to answer them.