Huh, not quite sure...
I played World of Warcraft on and off for several years, that's probably eaten up a few hundred hours. Same with League of Legends. DotA2 claims I've been logged in for more than 150 hours by this point, which kinda adds up. I also did about a dozen or more playthroughs of Baldur's Gate 2 in my life, which has got to account for 100-200 hours. Total War games took their toll as well, especially Medieval 2 (best TW game to date). Then there are the Bioware RPGs... I played through Mass Effect 4+ times, same with Mass Effect 2. Did at least 3 playthroughs of Dragon Age. KotOR had its share as well.
And THEN we get to a bunch of other games that I played from start to finish multiple times, like Planescape Torment, Fallout 1-3, Icewind Dale, Baldur's Gate 1, Warcraft 3, Starcraft, etc...