Halo 2 is, without a doubt, the greatest game. Even the glitches/bugs in the game made it more fun and competitive. No DLC, no creatable classes, nothing overpowered. Just simple, basic combat. It was so popular, and either Matchmaking or Custom games could be enjoyed by so many people. It really was the only game I played, so I'm obviously biased, but I've tried other games and hated them. Halo 2 was just it.