I have never downloaded a textbook for class, but I have downloaded various types of books for other purposes.
I am still trying to adjust to reading books on screen. For some reason I have no problem reading just about anything else on screen, but books are terrible (maybe its because I dont want to read the book?)
But a halfway point in between ripping students off in bookstores and online is a rental system. I know I have heard a lot of people starting to talk about it, possibly university system wide!