I would get the curve. Im a uni student and a bunch of my friends have a curve and love it. One of my friends even gave up his iPhone for the curve. It has a really great form factor and the little 'pearl' wtvr they call their scroll wheel is fantastic. the only complaint is that the web browser is really bad.
Personally i have an iPhone and i use it for school, the email and the calender are really good. but to each his own.
Oh and the iPhone is great for cheating in class, i just upload my notes as pdfs and then i can check them out during a test