I convinced parents about 25 years ago that their kids would have to spend an additional $2500 or so to bring their own computer into my department for their educational needs. The parents didn't flinch as the case I made for them needing that computer was logical.
Most college kids (on my campus anyway) already lug a laptop around. Some have moved to netbooks that are lighter and cheaper yet run all of the "required" programs.
For a tablet to make inroads at my university it would have to run the same apps those netbooks run. It would have to be priced the same or cheaper than a netbook. It should be able to survive backpacking across campus every day, rain snow or shine, for two or three years.
I don't see an Apple tablet being college survivable. Netbooks/notebooks at least can fold down to protect their own screens.
I really dont see it replacing notebooks/netbooks period. I see it as something a college student will have aside from their notebook and it will contain all their textbooks. but they wont be able to use the tablet to open up office or iwork and type a paper or save their files to print them in the school lab, or bring them up in class.