I'm not a parent (current HS senior here!) but I've read through a lot of this thread, and I've done my fair share of visits so I wouldn't mind sharing my impressions.
GWU- felt similarly to how a lot of other posters feel. Didn't like that there was no real campus. 3 kids from my HS have gone there in recent years, but they all transferred out, which makes me nervous. Won't apply.
Penn State- literally, you're on the highway driving past farms and cows and hay bales and more farms, and then all of a sudden there's a giant football stadium. I didn't like that. Won't apply.
Pitt- very urban campus without sacrificing green space. I really liked it! I've applied and been accepted, but I probably won't go- too close to home.
American- HATED it. On our tour, a group of kids walked by and yelled "Get out while you still can! This is a hell hole!" I also felt like it was too focused on getting kids off campus for internships and study abroad rather than what goes on in the classroom. Won't apply.
U of Maryland- a really beautiful campus, but very large. It reminded me of Hopkins meets UVA and I was pleasantly surprised. College Park is cute. I've already been accepted to my safety schools so I won't apply.
Georgetown- spent 2 weeks there for a summer program, and I loved it. It's very hilly, but the on-campus food is surprisingly good. Georgetown itself is a really affluent area, and I feel like the school is a bit too pretentious and politically focused (I know, I know, it's DC- but still). Considering applying.
Hopkins- really pretty buildings, but the campus itself was almost too perfectly manicured. I saw absolutely no kids there other than the ones on tours, and it was a Saturday afternoon in June so that creeped me out. I've talked to 2 students who went there, both transferred and hated JHU. Won't apply.
Tufts- I thought it was absolutely beautiful. I didn't like that the campus was soooo far from the T stop (the T is like the subway in Boston). People in admissions were very friendly, and some parts of campus had great views of the city. I just get the feeling that it's very, very liberal, which makes me feel like I'd be a bit out of place. Will apply.
Harvard- visited simply as a tourist but I didn't see what the fuss was about, it certainly wasn't that pretty. Stopped in admissions to ask for a campus map and they rolled their eyes and weren't able to get me one. The library looked nice from the outside, but the kids walking around campus looked like they hadn't seen sunshine in months. Dorms looked horrible. Cambridge is a cute town though. Won't apply.
MIT- drove through parts of campus on a Boston tour and it actually looked really cool. Didn't get out of the bus, so I didn't really get a feel for it, but it did look interesting. Won't apply.
Boston U- I thought it was a really neat campus. More defined than GWU, but I didn't love it. Very urban, the T is right there which makes it easy to get downtown. Still some green space and ADORABLE townhouses for students. A very cool school, but I won't apply.
Boston College- campus was too gothic. People in admissions were about as unfriendly as they could come. Asked for some info packets, they had none. Asked for directions to bookstore, they seemed confused as to why we were asking and they ultimately pointed us in the wrong direction. Too many steps and hills, and I hate that half of freshman live off campus and have to be bussed in for classes. Won't apply.
Vanderbilt- my absolute dream school, spent weeks there this past summer for a program. The campus is spectacular with magnolia trees everywhere and it's very flat which is nice. Beautiful facilities and killer freshman dorms. Very safe campus and surrounding areas are fun and nice. Medical center on campus is wonderful. Admissions office was very helpful, my tour guide was AMAZING and hilarious. I ran into him on campus a few days later and he said hi and we talked for a few minutes. Reflected very well on the school. Applying ED.
William and Mary- loved the campus. Williamsburg is a cute town and the campus was so green and beautiful. Loved the sunken gardens and history on campus. I wasn't signed up to do a tour, but when I stopped by the admissions office to pick up some information, the Student Body President offered to give me and my family a personal tour (!!!!!). Was very impressed by the attention they gave even though it was a Wednesday afternoon in January and they surely had other things they could be doing. Will apply.
U of Virginia- wasn't overly impressed. I hated how at the info session they made every kid stand up and say where he/she was from and what HS they go to. Campus was very muddy (it was January) and I just wasn't hugely impressed. Probably will apply.
Woo, this was long! Guess those two years of visits have to come in handy somehow