Spartan R41:

• Left 4 Dead is an old game, it came out last year. It's already gotten it's awards, and for the gaming industry no one stays on top forever.
  
• Rock Band 2 - as well as the entire music-simulation genre - is an old horse. They dominated for a while, and received several awards already.
• Modern Warfare 2 JUST came out, and isn't the "Messiah Game" that everyone makes it out to be. It's not going to win too many awards in it's first month, I would be willing to bet.
  
  

That's where your argument has it's faults. This is the best Xbox 360 game ever, not just this year. They deserve the awards, not Halo Wars.