So GameStop has what I can only call a scheme for Modern Warfare 2. (Have we officially decided to not call it Call of Duty: Modern Warfare 2? Less words to type!) If you pre-order the game (Xbox 360 or PS3 version only) from there, and return it by December 13, you'll receive a $40 in-store credit. In other words, if you pre-order the game, you'll get to play it for one month for a grand total of $20.
The problem is that the game just cannot be totally enjoyed in merely one month; multi-player will last for months beyond that. So you'd have to be cool with rushing through single-player mode, then only playing muli-player for a hot month.
And you'd also have to be cool with considering $40 in GameStop credit worth as much as $40 cold hard cash.
Never mind that you could rent the game from GameFly from $9 per month, for as many months as you want.
I'd advise you to skip this "deal."