I've invested a lot of time in a couple of games. A lot of time. Like, I'm ashamed-time.

Final Fantasy X - 170 hours

Final Fantasy Tactics Advanced - 86 hours

Elder Scrolls III: Morrowind - 3000 hours

Elder Scrolls IV: Oblivion - 1400 hours

Elder Scrolls V: Skyrim - 700 hours

World of Warcraft - 9432 hours (393 days)

Legend of Zelda: Ocarina of Time - 5 or 6 playthroughs, 100%, so I'd say around 100 hours
Legend of Zelda: Majora's Mask - 4 playthroughs - 40 hours

Dragon Warrior III (GBC) - 3 playthroughs, so probably..200 hours?

What about you guys?

Morrowind, Age Of Empires 2, Anno 1701.

According to Steam, Skyrim is the game I've played the most with 152 hours. However, there are a number of games I know I've played more than that.

How much I've played it I do not know, but the game I've played the most this console generation is most likely Mirror's Edge. For almost 2 years I played game pretty much on a daily basis. Granted, it was pretty much just "start the game, run thru a level, quit" but still. And I'm quite pleased about my Speedrun times too

But the 3 games I've played the most are all from the 90s.

• http://en.wikipedia.org/wiki/The_Elder_Scrolls_II:_Daggerfall (pretty much the only game I played for 2-3 years)
• http://en.wikipedia.org/wiki/Frontier:_Elite_II (went from a 100 credit bum to a multi-billionaire)
• http://en.wikipedia.org/wiki/Gunship_2000 (still waiting for a helicopter simulator that is more fun to play)

Civilizations by far. There was time Civilization series was only reason I remained as gamer, hell I even remember Civ 1. I think it was 2005 or so, when there was lots lots of crappy games, luckily they've improved now. Recently Rift, I played it 15 month, almost 4000 hour.

My top 5 according to Steam:

Terraria - 169 hours

Skyrim - 151 hours

Mount & Blade Warband - 121 hours

Civilization V - 91 hours

X3 Terran Conflict - 58 hours

I've played some other games for longer though. I think the game I have the most time clocked is Disgaea on PS2, but I lost my saves so I'm not sure exactly how long (pretty sure it was over 400 hours).