Mass Effect 3: 141 hours - I spent a lot of time playing the multiplayer with friends, even after we beat the game.
Gears of War 3: 140 hours - Played a TON of Horde mode with friends, along with all DLC.
Borderlands 2: 103 hours - Played this on 4 person co-op, and did a lot of item/achievement hunting. Being campaign only, this number probably has less padding than some of the others.
Skyrim: 120-130 hours - Raptr says 98 hours on the Xbox. I spend 20-30 hours on a friend's Steam account before I bought the game.
Dead Space 2: 72 hours - Wow, I must have played a lot more multiplayer than I remember. I also did 2 playthroughs, at close to 15 hours each.
Black Ops 2: 68 hours - 100% multiplayer. I'm sure this is tame compared to most people who play CoD games.
Gears of War 3 Multiplayer BETA: 57 hours
MW2 and BLOPS1 would probably be higher than BLOPS2, but I wasn't using Raptr at the time.
From before I could track play time:
Day of Defeat: (mostly 1.3b I think, some 2.0) I played a shitload of this. I even made custom flag skins and shit.
Diablo 2: I spent 3 months playing this daily, at 12+ hours a day. Some days I would only eat/bathroom/Diablo and end up playing for like 16 hours. (Diablo 3 lasted me a week, then I was bored and stopped logging in)
Minecraft: I played a LOT of this during it's initial boom of popularity. I did it all alone too. It wasn't until later when a couple friends finally decided to get it that I played it with others, but they got bored after a week or so.
Final Fantasy Tactics: I did a 100 hour playthrough and never finished. I think I was up to the final dungeon but it was too hard so I needed to grind out some XP. I never did.
Dark Age of Camelot: I played this almost daily for about a year. Then WoW came out...
