Fable
Halo 2
Too old. They weren't even available for the Xbox 360 / PS3!
False, thanks to the wonders of backwards compatibility. I was playing Halo 2 multiplayer on my 360 up until the day when they finally shut the servers down.
Incidentally, Halo 2 would be my pick. It was pretty much singlehandedly responsible for kickstarting (damn it, there's another good turn of phrase ruined forever) online console multiplayer, which is one of the most important things in the history of console gaming.
If we're going to limit it to games first released on 360/PS3...
Hm. Well, purely in terms of hours played and the impact on my life, Halo 3 without a doubt. My closest circle of friends in secondary school were the people I played it with. Fallout 3 certainly deserves a mention, despite the problems with it. Oblivion as well, even if it was far better with modding. Dark Souls is probably my first runner-up. Mirror's Edge was pretty great as well.
Honestly, and I'm really trying to put this kindly, but... IMO DA:O was the signal that Bioware had long since run out of the sort of creative juices that were responsible for gems like Baldur's Gate and KOTOR. Dragon Age was perhaps the
worst "good" RPG or AAA title I have ever had the misfortune to play. Most of the time when I stop playing a game, it is because I've burned out. When I stopped playing DA:O, it was because of a mixture of shock that it was really that terrible and shock that I wasted money on it. I don't think anything in a game has ever pissed me off as much as the illusion of choice & freedom woven into the very fabric of it.