I love Rochester because students are, in general, pretty smart, but no one brags about it or acts competitive at all. Thats definitely a benefit over big-name schools like the Ivy's, people want to do well, but not at the expense of their friends.
Honestly, I think I've participated in less than 5 "intellectual" discussions in my time here. I distinctly remember the first one, the spring of freshman year a bunch of us ended up talking about philosophy and religion for many hours into the night, and were then really excited that we had finally done something so "collegey."
There are TONS of freshmen who are pre-med bio majors (pre-med is not a major of its own). By junior year, there are significantly fewer. The stereotypical progression is pre-med to econ to psych. I know several people who have made exactly those changes in their major.
With all the people who think they want to do bio at the beginning, the intro bio and chem classes are pretty big. Of course, most all of the science classes I have taken thus far have workshops as well, so in addition to 3 lectures a week you have a 2 hour timeslot where you meet in small groups with an undergrad TA and generally do problems. Now all the science professors love these and constantly tell us how educational research shows how great they are, and it's true you often do learn a lot more in workshop than lecture, but they are usually in the evening and kind of painful to go to. College literature often emphasizes small class size and not having students as TAs, but it's really kind of nice to have someone not so intimidating you can ask questions and complain about the professor to in workshop. It's also a really good job/resume booster for people who did well in the class.
If you get a 4 or a 5 on the AP biology test you can take an alternative freshman biology sequence, which I did and although the first semester is fairly difficult it was very interesting. The professor, Dr. Platt learned everyone's names within a few weeks (over 100 people). I had him again for biochemistry and he again, new the 250+ students' names.
I got a job working as a dishwasher at the beginning of freshman year, which was one of the best things that ever happened to me. I have continued working there, moving my way up to doing research, and I adore the professor and everyone else at the lab. There is an annual lab holiday party at the professor's house, and I've gone out to lunch, the movies, and a bar with them on various occasions. I have not done this with any of my other professors, although I think people who are TAs for professors get to know them pretty well too.
The school likes to brag that the only required class is the writing requirement, CAS 105, which is true. That was probably one of my least favorite classes ever, but I know some people who have taken fun ones too. Basically it depends on the professor and topic, because there are a lot to choose from. Prepare yourself for lots of BS writing assignments in that though.
The whole cluster system for a liberal arts education is actually really cool. The college is divided into 3 groups: social sciences, natural sciences, and humanities. To graduate, you have to have a major, a minor, or a cluster in each of those groups. A cluster just consists of 3 somewhat related classes. I started a cluster in linguistics, which I knew nothing about, and now I'm minoring in that. Out of all the classes available in those groups, usually people can find three that interest them.