BioShock! Easy achievements. Only twenty dollars new. So cheaper if used. Loved the game I'm playing again on hard to get two of the 4 achievements I have left to get.

Modern Warfare 2. Excellent campaign and spec ops is awsome and little frustrating when you get stuck. Don't care for multiplayer that much.

Fallout 3: Game of the Year Edition. It's a fps/rpg it's fun and will keep you busy. Plus the extra content will grant you more guns more perks and more baddies to kill.

Those are my three. I want BioShock 2.