Kindle?
Everyone keeps talking about that thing, but it's a device I've never really been all that impressed with. It's still not as nice as compact as an iPad, does a hell of a lot less, and lacks backlighting and a color screen. On top of that, it's not really ideal for college student since Amazon's book store isn't really textbook focused. Also, the Kindle won't read PDFs or any other sort of file for that matter, making it impossible to make use of the eBooks one already has.
The fact that the iPad runs an office suite (iWork) is also a nice bonus, allowing students to write notes and such and class.
EDIT: As for comparing this to other devices, I must admit the tablet sector is not something I've been paying attention to. The last time I personally used a tablet/laptop hybrid was three or so years back when I used an HP TouchSmart TX1000. That thing was such a slow, disappointing, overpriced, and expensive joke (especially when running Vista) that it caused me to (perhaps wrongly) write off any other PC tablets ever since. It doesn't help that even now the only tablets I see people using are of the clunky variety.
Either way, I've always felt like a tablet needs to be an all-or-none device. Either be a laptop/netbook or a tablet, not both.