Dota2: 3,773 (I wonder how much would grow if it counts Dota1)
The rest is from memory but,
MonsterHunter 4U and Generations were around 500 hours each.
Fire emblem awakening and Conquest were at 300 I think rofl
Pretty sure other Fire emblem games from my childhood would also be good contenders, but who knows.
Something may be wrong with me.
Other games I can think of that I've put hundreds of hours into is The Elder Scrolls 3: Morrowind which I still love to death with easily over 500 hours on top of the time I spent making my own mods with custom dungeons, fully written and scripted quests and monsters (sadly not with my own models and animations) as well as the Dark Souls series of games which I am ALWAYS coming back to. Well 1 and 3 at least, I don't care much about 2 at all.
Hard to say, but no more than 300 hours I'm sure. It's possible I might have broken the 300 hour mark on older games back when I was a kid and didn't have much to pick from. Back then I'd play the hell out of what little I had available, but there's no way of knowing for sure.
World Of Warcraft
Been Playing Since Release in 2004.
Over 4 Years /Played between Characters.
What Have I Done With My Life. . . .
The largest amount of time probably goes to Super Smash Bros Brawl. While I've dumped an enormous amount of time into every Smash game, its the only one I had a lot of irl friends to play with.
Barring fighting games and MMOs since those are kinda obvious, I think it would go to any of the first 3 Disgaea games. I spent 100-150 hours each on them. Or maybe Tales of Symphonia since I've replayed it so many times over the years...
940 hours of The Sims 3 :D Probably 900 hours of building and creating sims
Phantasy Star Online episode 1 & 2
Longest time? A week. The game? .... Cuphead.....
man you have no idea how long I played gtaV. Hell I got no friggin idea.
1700+ hours on Terraria. Most likely far more on Minecraft.