I have Evernote and PDF Reader Pro though I'm not a student now. The former is good for taking notes, and the later is very easy for me to read PDF files with a paperless environment.
I have the free version and this app is great until the latest update. I can't post my reply on my friends' status. Overall this app is still the best app for Facebook!
I have 40. Most of them are games, but I don't have much time to get familiar with them. 474 apps sounds pretty crazy. Do you actually use them all once?