After FarCry (2004) No game has impressed me more than COD4. The single player mode is just a first person shooter as you almost can not wish him better. All of the party. Great soundscape. Broad range of different weapons, different levels, good graphics (for non-high-end PC's).
Negative fall on only the short playing time, and the lack of beautiful cutscenes. But Well, let's see if "Crysis" is even better!