SH 4 with the mods ruined FPS for me.Now I enjoyed Call of Duty World at War because finally had a land war game in the PTO, although it couldve been much better had it focused on the PTO exclusively.
FPS are just too scripted, I do not really enjoy online play because its mostly teenagers.I'm in my early/mid 20's but teenagers get annoying.So I enjoy the single player myself, problem is, you can only play through so many times without getting bored.
I still got the new COD and played it through on various difficulties, but its just too predictable, nothing like a good sub sim