Now, first of all, every one of these games is great in it's own way if you ask me. Not looking for meaningless wars, just curious what people's favorite shooter is and why. Let's keep it purely conversational and respectful :) (and don't hesitate to point out what I left out of the choices)
I say BF: Bad Company 2, because of it's superb balance of weapons and excellent map design. I will take Battlefield's immense scale and teamwork-based gameplay over the more personal and twitch-based CoD games any day. I'm a big fan of Halo Reach, but I can never play more than a match or so at a time without getting bored.