I would say Call of Duty 2, but you really shouldn't rely on me. Thats the only one of the three I have played. Still, its addictive game play with a variety of missions that you can steadily make progress through. But theres only like 8 or 9 missions (3 or so for each nation - American, British, and Russian). The only replay value is pretty much playing through your favorite missions on a harder difficulty. I had a good time with it at least.