If you own a desktop, I'd recommend the MacBook Air. I have one, and it's fantastic. Super light-weight, nice bright screen, and fairly fast. The battery life is great and with all the heavy books, the light weight is worth it. You can install Windows for test-taking, too. That said, if you don't have a desktop it's harder to recommend the air. I use mine almost exclusively, but I do have a desktop to fall back on if I need a CD/DVD Rom, or a little more processing power.
I don't own a desktop at the moment so the air might not be for me. I did go and look at it however, and it is indeed a nice one