Battlefield Bad Company 2. If you're playing on PS3, buy the game and be done with it -- if you're planning on playing it on PC, make sure you have at least 4GB of RAM, at least a 1GB GPU (such as the 1GB GTX 460; Asus, Gigabyte and EVGA are good brands), and a quad core CPU, the i5 2500k is a very good choice if you're planning on upgrading anytime in the near future, as it's clockable to amazing extents without much of a cooling requirement (if you do end up upgrading to it, get the P8P67 as your motherboard assuming you don't need more than 3 SATA connectors (see: here).
Hope this helps. PM me if you want game-specific information, system requirements or my opinion on a game's gameplay.