I sell games that take a long time to beat and I know I won't play again when I finish them. I have sold 4 games and have 7 now. Plus, I have 10 VC games.
Wii Sports **
Wii Play **
Metroid Prime 3 (on ebay now)
Resident Evil 4 **
Super Mario Galaxy **
Zack & Wiki (on ebay now)
Medal of Honor: Heroes 2
**won't sell these.
Have sold...
Godfather Blackhand (great game)
Excite Truck (great game)
Zelda Twilight Princess (great game)
Madden NFL 2008 (meh game)