1. Halo 3

Best FPS for the 360 hands down. Must-have for anyone who liked Halo 1 & 2, and all FPS players.

2. The Orange Box

5 games in 1? Good deal! Half-life 2 is already the Game of the Year or 2005, and Orange Box has Episodes 1 and 2 too, along with Portal and Team Fortress, 2 games that turned out to be surprisingly fun

3. Oblivion

Sequel to Morrowind, possibly the most complex and massive game out there. All environment, all the creatures, humans, buildings, you can interact with. Takes a minimum of 50 hours to beat.

4. Call of Duty 4

Great gameplay, great graphics, great multiplayer, the best ranking system. Get it.

5. Forza Motorsports 2

Gran Turismo killer. Graphics are amazing, over 300 cars, all modeled ridiculously well, damage is realistic, the driving is accurately simulated, and even though the pace might be a little slow compared to the more arcade-like games, its addicting and fun.

6. Gears of War

Graphics and gameplay. Need I say more? A good game to play when you need a break from FPSs.

7. Project Gotham Racing 4

A good arcade-simulation racer. You can ride motorcycles too.

8. Bioshock

Original idea for an FPS. Pretty scary at parts, and the gameplay is fun.

9. Mass Effect

If you liked Star Wars KOTOR, you will love this. If not, you should still rent it.

10. Splinter Cell Double Agent

Great spy action, hard as hell in some parts. Good to play while you wait for NINJA GAIDEN II!