What game have you played most (in hours)?

Total: 348 hours.

+Offline playing during a while, I roughly estimate about 400 hours in total playtime, more or less.

Dark Souls II

World of Warcraft roughly 2000 hrs

Fallout: New Vegas - 560 hours 'officially' but since my current FNV4GB-launcher doesn't seem to even log any time during my latest playthrough it's probably closer to 760.

Steam http://screenshot.ru/5b75b834d071fc373c19fa2e3e119607.png
Non-Steam - World of Tanks, ~ 3000 h

WoW.
86 days /played on my main when I left (shortly before MoP).

age of empires 3, i play since 2007 , only multiplayer,, probably 5000+ hours

I think it's WoW, from vanilla to the frozen addon i played 5 hours per day, 5 days per week.
In steam, i can't really say, i used to not close my games when i leave, so the "official" number means nothing. I think it's stronghold kingdom tho.

1. Garry's Mod- 378 hrs on record.
2. Age of Empires Online - 165 hrs on record.
3. Starbound - 89 hrs on record.

1. counter strike 1.6 - 1,400 hours / 2. cs go - 690 hours ..... yeah ,i like fps competitive

Left 4 Dead 2
277 h :)

Not long ago it was The Binding of Isaac
but a bunch of friends made a Terraria server and now I mostly hang out there :D

Played alil bit of Dota 2 ... Fun game , getting better @ it after 1000 hours

Psh who plays games in hours? Usually I play games in Ounces or Newtons, but as far as 'hours' games go it would have to be Borderlands 2 at 1128 hours for me

Dark souls 2
over 1000 hours
But after losing my progress once due to a hacker corrupting my save file, having to face hackers everyday with absolutely no effort from fromsoft to fight the problem, and watch the community be splitted in half due to a stupid dx11 update that should've given for free, but is instead being release in the form of a full priced new game, I'm done with it...

The Secret World: 6,497 hrs on record
Zombie Panic Source: 2,547 hrs on record
Killing Floor: 1,585 hrs on record
Counter-Strike: Global Offensive: 1,415 hrs on record
Team Fortress 2: 1,253 hrs on record

TBOI vanilla !

my main in wow have 193 days online and thats only him i wont count my 10 alts

Call of Duty: Modern Warfare 3 - Multiplayer: 734 hours

Call of Duty : Modern Warfare 3 504hours

Everything was ok until the hacker nation attacked.

:(

WoW: The creator of the lifeless.

1. TF2 - 564 hours.
2. FTL: Faster Than Light - pretty 100 hours on Steam plus 20-30 more on DRM-free version.

Dota 2 with 2367 (not gonna stop till 5000 minimum)

monster hunter tri 1000+ hours