Which 3 games made you expend more hours playing?

1. Garry's Mod : 1,500 Hours
2. Team Fortress 2 : 476 Hours
3. Counter Strike Global Offensive : 325 Hours

1st - Garry's Mod 2,363 hours (Also played before Gmod was on steam and the different updates that required a full new game install, also some before steam recorded hours)
2nd - Mount & Blade: Warband 1,407 hours
3rd - Counter-Strike: Source 484 hours
4th - Counter-Strike: Global Offensive 390 hours (Soon to pass CS:S)

1. All MMO-RPG games... just keep grinding for loots & exp
2. Torchlight II
3. Terraria... >_>

Diablo 2 -- Estimated 5k-10k hours
Path of Exile -- 1815 hours via Steam, maybe 2-3k from the open beta?
Terraria -- 1620 hours via Steam, 300 or so via a totally legal version before I purchased the Steam version.

Other contenders may include:

Realm of the Mad God -- played obsessively for about 2 years or so): 509 hours on Steam, no clue how many hours on browser (I only played the Steam version for a few months)
Elder Scrolls III/IV/V -- Lots of playtime over the years. I've picked each of these games up at least three times. I have a save file on Oblivion on my 360 with over 1k hours.
Two MUDs I played/worked on -- Played one very competitively over a long period of time (there were some breaks/ragequits, but I started in early '07 and played until... '10? '11?) as well as doing minor admin work. The other I worked obsessively on design and fixing others' mistakes.

1-TF2, 714 hours.

2-Probably some pokémon game around 200 hours.

3-Probably another pokémon game also around 200 hours.

Osu would potentially be in the list if i had any idea how many hours i've spend in it.

I'll have to estimate, seeing as how the gametime for all of these was not tracked properly.

1) Diablo II (9,000 hours)
2) Neverwinter Nights (7500 hours)
3) Counter-Strike (~6800 hours)

Honorable Mention:
--Left 4 Dead
--Unreal Tournament
--Warcraft 3
--League of Legends
--Lord of the Rings Online

What I notice about all of these games (except for the MMO) is that there's a base game, and then there's variation built into the game after that (maps, mods, randomness). Experience let's you get good at playing the game, but it's never the same experience, twice.

Hmm...

Borderlands 2 - more than 200 hours
Borderlands 1 - bought it on pre-order, non steam but I guess I've also played it for smth 200+ hours
Planetside 2 - +/- 190 hours

If we take only steam games (and so my time spend on BL1 wasnt with steam version) then I guess I'll take Skyrim with +/- 110 hours

I only play from "PC" with steam for almost a year.
1st - Counter-Strike: Global Offensive 497 hrs
2nd - Killing Floor 57 hrs
3rd - Saints Row: The Third 44 hrs