I prefer traditional books for the ones that I know I'll be using a lot or keeping in the future. For the "less important" books I'll use ebooks sometimes, but I have a hard time really digesting the info from ebooks. Ebooks are great for when you just need to look things up, though. Just my preference.
Also remember that you won't actually need all of the books that are listed for you, so definitely talk to some current students to find out which books you'll actually need before you go buy them.