why would you sell a videogame? I did that with N64 games once and will never do it again. You lose money and if you ever want to get the game again you'll lose even more. I have lot's of old games (for this generation alone) I'll probably won't play for the rest of my life like bfbc or gow. I'd advice to just keep the game, maybe splash damge decides to put a lot of effort in it.
I am selling them to get new games. Since Im selling the games I tried out more games in the last few month than before that in years. So it may look like I lose money, but I get to try new games for much cheaper. And the memory of the game stays.
I sell a game if im sure that I wont want to play it again. I sold gta 4 for example because I could get it later on PC if I want.
But yes there are days when I have nothing to play with:P I currently have only 3 games:P