CoD4 also.. have been playing multiplayer on Xboxlive.. great fun.. didn't know that i was able to connect, cuz it said that i couldn't get connected to xboxlive from the Marketplace. I have to admit, though, the campaign part is not all that great imo, i was actually rather disappointed, cuz my AI team mates are stupid (scripted) and can't see me, and your opponents keeps spawning and you basicly can't hide from them, they will see you no matter what, unless they are scripted otherwise or if you are sniping far away from the battle scene.