BFBC all the way for me, I dont buy multiplayer games based on how good the single player is. Battlefield games never used to have Singleplayer at all and they sold like hotcakes. I love multiplayer combat with ground and air vehicles in the mix. Cod4 has vehicles but were controlled by the AI. How many times when playing COD4 and the air support helicopter came in, did you hear the question, "Can we controll the helicopter?" Well in Battlefield you can along with Tanks humviees APC's and Attack choppers. There is nothing better than playing the spec-ops guy and hiding in a bush after planting C4 on the road and watching a APC filled with enemy troops roll right over it and pushing the Big Red Button! Or when you team is pinned down by an enemy tank pounding away and shredding their house that they sought shelter in to bits, after they call for help you come flying in with your Apache rockets blazing, killing the tank and saving your teamates. Seeing that same senario from the ground is awsome when you have a good pilot backing you up! Battlefield has always been the King of Multiplayer for me, the Huge maps are Great, they are the ones that started the whole Rank and Awards system with BF2, Attack and Defend (aka Gold Rush) is a lot of fun dont believe what other fanboys tell you and try it for yourself, there will be the vintage battlefield mode called Conquest releasing soon along with maps specially designed for it, I did love Cod4 once but have moved on.