definitely the docking station
I would like the see one of the custom docking stations some users have made...preferably the wooden one.
Sometimes a "smartphone" is only as smart as its user.
any of the docks
those vinyl stickers for the back of the screen
how about a year of someone's favorite photo site?
could also do MOTM (member of the month) for varying reasons.
Since I already have the docking station... I think some cool apps to give away would be GDE, MyBackup Pro, Weather Widget, Documents to Go, Note Everything Pro and maybe PicSay Pro.
Granted I have half of those too but I am sure there are people that would like them.
OG Droid->Incredible->Droid X->Incredible->Incredible 2->Incredible->Samsung Charge->HTC Rezound