Good games for old PCs

[Dr Ravage]

Alpha Centauri (with Alien Crossfire expansion)
So many hours spent colonising the planet.

 

[NuclearPenguin]

Silent hill 2 (and 3 if your computer is up for it). Those games are extremely good, and I promise, you won't get bored.
Also, Abe's Oddyssey, Freelancer, Halflife 1 with expensions, Starcraft and Halo: Combat Evolved for PC.

Already finished Silent hill 2 and 3 for ps2.

 

[SilkySkyKitten]

Jazz Jackrabbit 2
Half-Life (and its expansions)
No One Lives Forever: The Operative
Need for Speed III: Hot Pursuit
Need for Speed: Porsche Unleashed
System Shock 2
Crimson Skies
Interstate '76
MDK
Quake 1, 2, and 3
Rainbow Six
Sim City 2000
Unreal
Unreal Tournament

 

[NuclearPenguin]

Jazz Jackrabbit 2
Half-Life (and its expansions)
No One Lives Forever: The Operative
Need for Speed III: Hot Pursuit
Need for Speed: Porsche Unleashed
System Shock 2
Crimson Skies
Interstate '76
MDK
Quake 1, 2, and 3
Rainbow Six
Sim City 2000
Unreal
Unreal Tournament

Nice list

 

[Firefly22]

If your into fps's you should try SHOGO:Mobile Armoured Division. Its a violent anime themed fps were you can stomp around in huge mechs and also shoot people on foot. You can get it fairly cheap on GOG. I would highly recommend it.

 

[end_boss]

X-COM: UFO Defense (aka Enemy Unknown)
Star Control 2

I *love* older games on the PC, but my tastes aren't always transferable to other gamers. These two are quite universally admired, though, and I don't think I've seen these mentioned yet, which is a glaring omission. LOL