First, let me say that I'm a Penn State grad, so I obviously have a bit of big-school bias 🙂 However, I agree with the previous posters in that you should, first off, go where you are most comfortable and believe you will be able to succeed. To be honest, as long as you do well in your pre-req's, maintain a solid GPA, and are at a reasonably competitive school I don't think vet schools care much at all about where you went.
That said, if you don't mind large class sizes for the first couple years (the pre-reqs mainly), a state school with a good ag program has a number of advantages. My major was geared toward pre-veterinary students (animal bioscience), the pre-vet club had over 100 members, I had a full-time pre-vet advisor with years of experience, etc... I also was able to spend two years in an immunology lab on-campus, minor in microbiology, and take courses such as veterinary parasitology, principles of animal disease, animal nutrition, theriogenology, comparative animal physiology, etc....
I should also note that there are small classes at large universities, you just have to wait until your last couple years for the smaller science classes to come around, and the humanities classes are usually 30 or so students or less. I've always enjoyed literature also, so the gen-eds I took included topics such as comparative asian literature, soc/pol philosophy, literature of australia/new zealand (I spent a semester in australia).
In general, I'm of the opinion that you can make a big university much smaller just by becoming involved in things that interest you. So, if you can learn to enjoy the larger classes and bureaucracy that go along with a large univeristy, the opportunities available to you as a pre-vet student will not be in short supply. (Oh, and I'm pretty sure I learned how to think at PSU, it's just easier to slide by there if one is so inclined 🙂 ).
