I'd go with the Macbook Pro. The fact that the Air only has one USB port, no Ethernet port, no removable battery, and that you can snap it in half with your bare hands (well, at least the screen anyway) really deters me from buying one. Not that I would anyway because I'm a bit of a Mac hater. And also, I want a laptop that I can tell that it is on my lap, I don't want to be typing on a feather.
My school uses Macbook Pro's and I've had a good experience with them!