Which old games do you like?

I just finished The Operative: No One Lives Forever, it's an absolutely amazing game.
Sad Addendum 1: Sadly, there will probably never be a third sequel.
Sad Addendum 2: Sadly, it's not easy to come by, and it isn't on steam or GOG (which is the best place to get old goodies such as this)

Rayman
Croc
Unreal Tournament
Midtown Madness

Pharaoh and Lego racers, i must admit i keep going back to them fairly often even though there are so many new games out there=P

Theme Hospital
Seven Kingdoms 1 & 2
Shadow Comapny
Motorhead
Pinball Mania
Supaplex
Grand Theft Auto
Evil Islands
Heroes of Might & Magic
The Settlers 3
Gruntz
Gothic I
Ghost Master
Command & Conquer Red Alert 2
Earth 2150
and many others

The Lords of Midnight, a great 3rd person fantasy strategy game from 1984, I've loved it since I was a kid. Still plays pretty good for a ~30 year old game.
Modern remakes for windows(GOG),mac ios ,android blackberry play etc. These are pretty good, graphics look like the originals but just a lot less pixellated and added convenience like an in-game map.
ZX Spectrum original here. [note: I don't know what sg's policy is on linking to sites that host old games so just in case I will point out that they have permission from the copyright holder]
Here is the best fansite (run by Chris Wild,the guy who made the new remakes with the original dev) which include a 90's free windows port

Warcraft 3, Megarace, Age of Empires 1/2, Red Alert 1.