Gears of War on Xbox 360 would have to be one of the greatest games I have ever played, and that includes both halo's. It is an especially cool cover system that allows you to duck behind objects and to shoot blinding over them. The plot is a little strange, and hard to follow, but it still remains an awesome game.
It is sort of creepy, but you are too busy shooting to really notice. I'm not even sure who the bad guys are?! They are some kind of underground living creatures, but they have lots of giant spiders or bats or something. Very weird, but awesome.