minesweeper, I'm not joking, this is the only game I play when I'm doing some maintenance works/driver updates in my PC

I never delete my games.

yes...Battlefield bad company 2

TF2 and dota 2?

Well not including the times I formatted my hardrive which obviously erased everything, Team Fortress 2.
Nowadays I have enough hard drive space, so I won't need to delete any games again for at least 5 years.

World of Warcraft >_<, The Elder Scrolls 3, Pax Imperia.

Once I install a game, it stays installed.

Tf2, killing floor, L4D2 (just in case), Stalker (until just recently)

Man I hated farcry 2. Did you even play the first?

Quite a few now that my hard drive's bigger. All my Sonic games stay, all my Tomb Raiders, a handful of favorite racers, Croc 2 which was a childhood favorite, Skyrim and Minecraft for exploring, Saints Row the Third for being a jackass in, Audiosurf so I have something to do while I'm just listening to music, FTL recently earned a spot since it's so easy to jump in and out playing... and I'll admit I keep Sims 3 around to toy with. Then if I get into emulators, that's another handful. lol Mostly Genesis titles since I don't really like being stuck sitting at a TV with a bunch of people around me.

edit: Looking through all these somehow reminded me of a game that's been on every PC I've had since sometime in the mid-90's. It's a snake game called Wrigglers (though you're a worm instead). Nothing particularly remarkable about it. It's more like a rite of passage to install it on each new computer. lol

GTA Vice City.

Quake III Arena (never uninstalled since 1999, always synced the folder with a fresh Win install)
Deus Ex (same as above since 2000)

Entire Hitman series and the original Deus Ex.

Audiosurf and Minecraft because they're endless, and Braid because it's so awesome.

Morrowind

Bastion. Its a work of art.

Company of Heroes

I would of said CSS i had a copy installed since got the silver pack for steam and was playing the early builds in 2004. Would always be my go to game jst to play stuff and saw a lot of my servers become my favs then get shut down. Deleted it this year after not playing for ages and not really liking CSGO as much. But man 8 years of dragging the same install from pc to pc.

TF2 and L4D2. Simply because I don't want to bother downloading all those files again -_-

Diablo 2, commandos 2, and counter strike

I believe the oldest game I still have installed is Battlefield 2142, which has been installed since 2006.

Edit: I'm wrong, the oldest is Counter-Strike: Source, 2004.

Halo PC/Online play is still strong to this day.

killing floor

THPS HD

For da Nostalgia