I'm this won't come as any surprize- Bioshock one and two, it just has more than the same old people to shoot at, it felt like everyone in the city had a story to tell and a personal reason to fight you (until you killed them of course). Add Andrew Ryan, Little sisters, the city itself and it's ten year backstory and you have a game that in my eyes cannot be beaten.

I do also really like the endlessness of Fallout 3 though