How much can I sell my xbox 360 and games for?

I have xbox 360 arcade with 2 wireless controllers and hand wise I have ncaa 11, madden 10, assassins creed 1 and 2, tony hawk ride(with skateboard controller), tom clancy hawx, nhl 10, mlb 2k10, sega superstar tennis. Red dead redemption' modern warfare 2, cod black ops my question is how much should I ask for this on craigslist? Or if I had to how much will gamestop give me in store credit?