Let's see...some of the stuff I had in my dorm rooms (and I lived in the dorms for 4 years):
Mirror to hang on the wall
Several power strips
small tv
small fridge (unless your room already comes with one - some of mine did)
small microwave
if you're a coffee or tea drinker - a Keurig or something similar
Mounting putty or command hooks for hanging stuff (not allowed to put nails in walls)
Some pictures or posters (get the posters laminated - they'll last way longer)
a small bookcase (or you can use stackable milk crates or something similar)
an iron and mini ironing board
bedding and pillows
towels
Dorm room mattresses are usually pretty flat - an egg crate or memory foam topper and a mattress cover is nice
If you have a community bath, then flip flops, a bath robe, and a basket for carrying your bath stuff
a few dishes for eating in the room (plate, bowl, cups, silverware)
a laundry basket for taking clothes to the laundry room
a tv tray or lap tray - nice for doing things while sitting on the bed
ummm - that's all I can think of for now!