Though I'm an avid console gamer, I'm not into PC games much.
At least I wasn't.
Has anyone played the DayZ mod for Arma 2? Excellent example of what mods can do for game franchises (although I believe the modder is a member of the Bohemia development team).
Anyway, superb little game. I recommend checking it out (Arma 2 is actually pretty good in itself too, but pales in comparison to DayZ in my opinion).