What Steam game have you the highest playing time?

F1 2013 - 111 hours.

Skyrim 155hrs and still not completed...

1. Dota 2 - 923hours
2. CS:GO - 152 hours
3. TF2 - 90 hours
4. CS:S - 34 hours - + 200-300 hours, because I was fcking warez guy. I'll never do this again!
5. Awesomenauts - 20 hours
6. Portal 2 - 19,9 hours
7. Borderlands - 19,2 hours
8. COD:Black Ops MP - 17,7 hours
9. Path Of Exile - 17,4 hours
10. War Thunder - 16,2 hours - + 20-30hours because Ive installed it before it came on steam.

Team Fortress 2 - 2286 hours

Guild Wars 313 hrs

Team fortress 2: 1890 hours, in reality even more, I had another 500 on a different account.

Counter-Strike - 5,375 hrs
Dota 2 - 2,136 hrs
Counter-Strike: Global Offensive - 294 hrs

As a personal project I gathered data from 17K random public profiles. Not a big sample but...
http://i.imgur.com/dgxILZO.png

Just Cause 2 - 80 hours + ~100 hours before steam
Kung Fu Strike - 32 hours
Bridge Project - 25 hours

All other games are MMO type - Vindictus, Smite, Battlefied 3, SimCity

Burnout Paradise - 86 hours

Mount and blade Warband - 1060 hours played

Regiment and stuff. Got more hours because I played the native campaign on non steam before.

Dota 2 - 1063 hours.

CS 1,6 - 3k

Isaac, tho if my joystick didn't fuck up it would probably be PES13

Tomb Raider - 43 hrs

Probably All Points Bulletin.
Shit, now i'm missing it, haha.

Have a nice day :)

Team Fortress 2, 401 hours. Other noteworthy games are Killing Floor (236), PAYDAY 2 (164), Left 4 Dead 2 (116) and Fallout New Vegas (94)

warframe 1.078

Team Fortress 2 657 hours, I haven't played for some time but the game is great :D

My Top 5

1. Space Pirates and Zombies (152hrs)

2. Terraria (105hrs)

3. Shufflepuck Cantina Deluxe (71hrs)

4. Sid Meier's Civilization V (49hrs)

5. Killing Floor (47hrs)

cs 1.6 1331 hrs

Dungeons of Dredmor.

Call of Duty: Modern Warfare 2 - Multiplayer - 1,206 hrs on record
Call of Duty: Modern Warfare 3 - Multiplayer - 1,032 hrs on record

Sigh.

cs:go 353h
tf2 152h
ns2 59h