Games we loved years ago, that still stand the test of time.

American McGee's Alice -- started playing it right before the newer one came out, ended up playing all the way through
Vampire: The Masquerade -- tried playing it when I first bought it on Steam about ten years ago and got through a little, but really gave it time this past year -- still an amazing game

just noticed you said "two", so I'll save myself some time and stop there :D

X-Com series
Fallout series
Arcanum: Of Steamworks and Magick Obscura

Colonization is the oldie i play more

Battlefiel 2 (one of the parts before I started hating EA)

Worms Armageddon. It shows it was a good game when people still buy it 14 years after the release date and it's as expensive if not more so than more modern Worms games.

Jagged Alliance 2

Doom , Age of Empires, Roller Coaster Tycoon, and Unreal Tournament 1999 all seem to have gone through those years just fine, even though you can see they show their age on some aspects. Some more than others.

Planescape: Torment - for me still the best game I've ever played (the story and unlinearity are just unbelieveable!!) - I have this game ALWAYS installed on my laptop and keep replaying it over and over when for example travelling.

Uncharted Waters: New Horizons 2. I only wish that Sid Meyer's Pirates and now the new AC4 Black Flag were as bold as this game were back in the snes.

Neverwinter Nights 2 (and the original, as well). Just so amazeballs. It's a (kind of) proper D&D experience, that you can play alone, and with a rather good story to boot :D

Flatout 1 - I don't know why, but every time I play this game, I rediscover what gaming is all about. You don't need fancy graphics. You don't need uber detailed, cinematic stories. You need things to blow up, and to have fun while doing it :P

Final Fantasy IX - Well, I suppose the best JRPG of all time must stand the test of time well, yes?

And, last but not least - Every Pokemon game ever. No explanation needed, right? Good.

There are many more games I could have put in this list here, but I don't want to write a wall of text that no one would read , so this is it :P

Half Life series. Brilliant as ever.
I loved Mirrors Edge a lot, and still do. Though it's not that old yet :p

Mass Effect series and Half Life 2

I love seeing games listed that are only 5 years old.

Goldeneye 007, Super Smash Bros, Golden Sun, Mother 2, Spyro the Dragon, Final Fantasy IV, Mortal Kombat 3, Mega Man 1-6

Fallout 1 and 2, Planescape: Torment, Beyond Good and Evil. I guess there's lots more , these popped up in my mind =)

Age of Empires II ! Bought the AoE:II HD as soon as it came to Steam for pre-purchase

For me, Star Wars Jedi Knight: Jedi Academy, but it will be dead in a year or so I guess :(

Master of Magic, Master of Orion 2, Sid Meier's Civs (1,3,4), Colonization, Alpha Centauri and it's expansion Alien Crossfire

Tetris and even classic pinball.

Monkey Island series (even Space and King's Quests to a degree). Humor is able to stand the test of time relatively well.

FF7. Nuff said.

The Legend of Zelda: A Link to the Past is still my favorite Zelda game.

And it's not as old, but the original Left 4 Dead is still quite fun.

World of Tanks

Ultima Online

Po Ke Mo n

Beyond Good and Evil
Psychonauts

Others would be; Diablo,
Lands of Lore,
Dungeon Keeper,
Tyrian,
Myst Games,
Another World,
Total Annihilation,
MDK,
Abes Oddysee and Exodus,
Transport Tycoon Deluxe,
Stonekeep,
Fallout series,
Crusader Series,
The Longest Journey,
Nox,
C&C Series - including Renegade,
Dark Reign,
Riddick Butcher Bay,
Balders Gate,
Temple Elemental Evil,
Dune games,
Alien Shooters,
XIII (annoying no sequel)

At least half the stuff GoG.com sells really.

One not known game that I liked is on steam since ¿today? Urban Chaos

Guitar Freaks 2nd Mix, Rollcage Stage II, No One Lives Forever 1-2, Unreal Tournament 99, Final Fantasy IV, Worms Armageddon, Hitman 2, Metal Gear Solid 2 and more...

Maniac Mansion / Day of Tentacle / Monkey Island 1 and Pong

Empire Earth, it was the first game that i really loved. +
Cäsar III.