I've used my laptop to take notes in some classes.
In my Curriculum Instruction courses we often do smallgroup work, so it's convenient to type the notes for the group and email them to everyone.
One of my Pol Sci professors loves to switch overheads before anyone can get through copying down the info and doesnt review much of what he said, so I type notes there since I type faster than I can write.
Having a laptop is good for providing evidence when I've corrected instructors.

Instant access to the data you need rocks.
That and there are days where it feels like I'm ADD or something- so having a background IM conversation during class keeps me sane.