I have a daughter who just finished the second and last year of dorm life (apartment in the fall). First, let me say, less is more. Both years her roommates brought everything they owned to this small room. It took them forever to move in and out. We were streamlined, and after a few trips up and down the four flights of stairs, we were finished.
Make sure your son has a GOOD chair for his study area - our daughter has had back surgery so the dorm supplied straight back chair would not do. Got a nice office chair (small - but she is small also) and everyone envies it. Also a good study lamp - no halogen - they tend to incinerate things from the heat they put out (voice of experience). Power strips, cords, OTC meds, laptop or desktop computer with printer (this is not a luxury - they can't get by without it), antibacterial wipes (for my peace of mind), a fan for bedside (drowns out noise from roomies). Also look into the meningitis vaccine that is recommended for college students (particularly those living in high density housing). Money is lovely - she loved unexpectedly getting $10 in the mail or a restaurant gift card. I gave her BF a Sonic gift card for his birthday and told him not to share!