I have a son who is a Sophomore in College and these are some things we've gotton as fillers for him and for his two 17 yr. old brothers:
A 'squishy" (micro-bead filled) pillow from Brookstone. They all love them.
Cologne & shower gell (matching)
Sneakers
T-shirts
Sweatpants
Hoodie
Earbuds
Gaming Headphones
Small rechargable shaver set (Sharper image)
Alarm clock that projects the time on the ceiling
Flannel Sheets
Nerf Guns
Last year we got some things for college, but not too many...the biggest was a thicker foam mattress pad. We had gotten one of the cheap ones when he first moved in. Got it on overstock and it wasn't too expensive.
The thing that seems to be popular this year was popular when my kids were young are "Bay Blades". It's crazy, but they're playing with them again
Stocking type stuff:
We've gotten things from "Think Geeks", too
Rubics cube
Slinky - silly things that they used to get as kids are always fun
"penny candy"
With 3 teenage boys I could go one forever...