I suggest you buy this, then take it to a local bike shop to make sure it's in good mechanical condition.

While Davis is a great place for biking around, you don't need much of a bike to get around. More importantly than getting the right bike, I would suggest spending some time learning how to ride properly. Get comfortable riding in traffic, maybe even navigating a traffic circle.

Also, it might be a good idea to learn a bit of bike maintenance, I suggest stopping by Bike Forth when you arrive.

Also, learn about Davis Wiki. See, I'm just full of help for incoming freshman.