I am a graduate student who moved from a 13" MBP to an 11" MBA. If I were you, I would not consider the MBP, because the latest refresh was a real disappointment. The resolution stayed the same, you still poke along with a hard drive, and it is way too much power for the kind of stuff you are likely to be doing. What is the point of spending more for less? I love the MBP line, and enjoyed my 2011 model, but there is no way I would recommend anyone purchase the 2012 MBP 13" unless they just absolutely had to have firewire or something like that.
Anyhow, if you could give everyone a better idea of other stuff you have (iPad?) and stuff you use (Pages, PDFS?), how much data you have (10GB, 100GB?), and how you intend to use it (carry to classes, use only at home?), then they could give you specific advice.