I got a deck of cards, a multi-tool, a few bucks(for the cards), my mp3 player, and a student ID(in case i get horribly dismembered or lost).
Bug repellent, flashight, and batteries were the first things to come too mind, assuming you already have the assentials such as clothes, sleeping bag, pillow, toilatries, etc.
Books.. deodorant.. fully charged cell phone..
thanks