What game should i get?

I have an Xbox 360, $60, and a thirst for a new game. I am really into RPG's, first-person shooters, and music games. I do NOT have Xbox Live, so i am looking for a game that would be a lot of fun without multi-player. I also want a game that wouldn't get old after about a week of gameplay. Borderlands is an option, Dragon Age: Origins is another, and so is Guitar Hero 5, but i want to know what you all would buy. Here is a list of games that I already have:



Fallout 3

GTA IV

GH: Metallica

GH: World Tour

Mass Effect

COD 4: Modern Warfare

Halo 3

Need for Speed: Carbon



What would you get?What game should i get?
Modern Warfare 2.