I use my 8820 (AT&T) without a data plan (I do however have a text messaging plan). It's alright if you don't need push email and can always connect to wireless ap. If your campus is like mine then there's wi-fi in every building so that's not too big of a problem.
As for BBM, it is a PIN messaging service and will not work without a data plan. However, there are other programs for IM that will connect via wi-fi (i.e. JiveTalk) so IM is possible.
As for text messaging, without cellular coverage you're pretty much out of luck. If you use an email client such as LogicMail which will connect via wi-fi you can email text messages but you will be unable to receive them. If the recipient has the means, he/she can email you the response but in that case you'd be better off using IM. This method of text messaging is not worth the trouble to do regularly, but can be useful in a pinch.
Sadly, I am going to be spending a lot of time in these lecture halls and I will certainly need something to do.
I've always found that listening to the lecture and taking notes works well for combating boredom... and bad grades.
Hopefully this helps. There's a lot of knowledge on this board, so if you have a question do a search and if you don't find what you're looking for just ask.
Good luck in school!