Mine has got to be Call of Duty: World at War. It had a pretty good story and it was super awesome to unlock the zombie mode after you complete the story. The zombie mode was tons of fun playing with friends and we never really had anything like it before. I also like the multi-player because it had some awesome guns and nothing was completely overpowered. My favorite gun was the Springfield without a scope. The maps were awesome too. They were exactly what the game was going for and nothing felt out of place. I like this Call of Duty the most because it is the only Call of Duty were I was better than my older brother too.