What we did for DS (recently graduated from UMich, but I love him anyway [Go State!])
Money, Snacks, stuff he needs but forgets to buy (toiletries, napkins, etc), money, current magazines, money; oh, and anything homemade: cookies, brownies, rice krispie treats.
Note from both he and I (his DDad): UMich used to offer 'care packages' that you paid for but they assembled and delivered - usually a student org. fundraiser. We tried them his freshman year, and they were crap. Snacks were a few bite-size candies, saltine crackers. A couple of drink boxes and a little box of laundry soap -> $25-30. Do it yourself; it'll be better and they'll appreciate it more.