Ever have a game that never leaves your hard drive?

Civ IV.
And Hearts too...go figure.

Unreal Tournament and Unreal Tournament 3.

never say never

Empire Deluxe for Windows. Had it installed on every PC I've owned since 1993 or so.

1nsane since 2000-ish.

OpenArena for 4-5 years as well.

Guild Wars and Killing Floor

Fallout 3, Half-Life 2, Left 4 Dead 2
And all my dearly beloved PC classics (Starcraft, Diablo II, Heroes III, Quake 1-3, Doom, Duke3D)

The entire Dawn of War series, both 1 and 2, are always installed on my PC.

CoD4 - CS1.6 & CSS

most of my steam library

L4D1 and L4D2.

Tf2 because i play it a lot plus my internet is shit and i don't want to download all the updates again. If i have to say reinstall my os i always back that game up because of the shitload of updates.

Solitaire always there...

phantasy star online blue burst :S

Morrowind. I have a few instances of it, each modded differently, or not working at all.

Also Progress Quest. Damn thing is so addictive.

Warcraft 3 with TFT expansion.

Still to this day my buddies sometime ask me to play. ;)

fallout 2

Recettear, Tobe's Vertical Adventure, and Terraria are the only three that have been there long enough to really count.

The 仙剑奇侠传 and 轩辕剑 series. Lol. That's my answer to just about everything.

caeser III
return to krondor
total annihilation

amazing games

Ehh I seem to never delete F2P games :p

Quake Live

Saints Row the Third will always be on my pc

The Sam and Max series. And Walking Dead.

Swat 4 (great LANs still occur with this one), Mount and Blade Warband (same reason), League of Legends, Dota and Dota 2, Command and Conquer Tiberium Wars, Planescape Torment, and some more.