Team Fortress 2
88.2 hrs
Pirates, Vikings, & Knights II
81.7 hrs
Counter-Strike: Condition Zero
35.6 hrs

LOL, I'm looking like a newbie in company of you :)

CSS - 22.2h
DiRT2 - 20.9h
Batman AA - 18.9h
HL1 - 17.8h

1 Skyrim 120 hrs

2 Knights of the Old Republic 25hrs

3 Battlefield: Bad Company 2 15hrs

4 Half-Life 2 (back in 200x offline) probably ~15-20hrs

rest under 5hrs (incl portal+portal2,counter-strike)

Garry's Mod
1222.6 h

Counter-Strike: Source
1033 h

Left 4 Dead 2
417 h

The Elder Scrolls V: Skyrim
338.5 h

Tom Clancy's Splinter Cell: Conviction
201.7 h

L4D2: 510.4 hours. Would be insanely higher if I didn't have this dumb thing called 'university' to go to >_>.

TF2: 113.7 hours, though quite a bit of that is probably idle.

Audiosurf: 30.2 hours; I'd say 75% of that time is spent playing "Through the Fire and Flames" lololol.

Killing Floor: 20.9

Portal 2: 14.2; Would like to play this more. No time :(.

Amnesia: 11.5

And then a bunch of <10 hrs.

Garry's Mod with 614hrs.

Gmod: 1267.9
Css: 435.5

but i have "borrowed" alot of games including skyrim, fnv, mass effect 1,2 and a whole lot more which id say would round up to about 500+ hours

TF2-206h.