Amazon still has Call of Duty: Modern Warfare 2 For the Xbox 360 With $20 Game Credit for $59.99 + free shipping = $59.99 shipped! This game is off the hook. I started playing it last night. The Campaign (single player) is folds better than the first and offers almost endless replay thanks to the online multiplayer and coop missions. The $20 credit will be placed in your Amazon cart and must be used towards a game purchase in the future.
Alternatively, Deepdiscount.com has it for $48.99 + free shipping = $48.99 shipped!