FF XI was mine... but I'm not a fan of MMOs.
As for normal games, I think Resident Evil 5 would be the latest one I can think of. The game itself wasn't bad. I even liked what little of the story I saw. It's just that god awful forced two-player gameplay that got to me. I play single player because of just that, I like to play on my own. I don't want some other character getting in the way of my shots, using all my ammo and then whining about getting beat up because the AI is so terrible. Worst part is that if I don't bother going off to save her, it's a game over. It's a major handicap on me as I have to waste time and healing item to protect this stupid bint who can't even aim right. [/rant]