Rainbow Six Vegas is just great altogether.
The story begins in a desert city in Nevada where you have to repel a terrorist attack, then gradually the story line changes to the streets of Vegas. The combat system is this game is much like the Gears of War style, hide and shoot but it also leaves room for run and hope you dont get hit style. The Multiplayer in this game is exellent with many different styles too choose from. From Capture the Flag to Elimination there is never a moment when you cant hop into a match and play.
The graphics are great but have room for improvement in some spots, so if you have Gears of War and gotten bored with it, this game is the next best thing.