How much riding around campus are doing. If you're just doing a 1-2 mile moderate speed cruise to class, I'd say just get a decent regular backpack with a laptop sleeve, which is what I did, though Gainsville is warmer and more backsweat inducing than Michigan State where I did my undergrad. The internally framed packs with lots of straps are nice for long and/or high speed rides where you don't want much motion and they're lifted off your back to reduce backsweat, but they're much more of a pain to slide under your chair especially in a big lecture hall than just a simple backpack. If you get a rack, any backpack and a bungee cord or cargo net makes life even easier.