First old game you think of

Total Annihilation

I'm not sure why, even though it was a great NES game and all, but my first thought? Crystalis.

Chrono Trigger

Wing Commander

gameboy pokemon series ~

Dino Crisis 2, one of the first "real" videogames I played.

Leisure Suit Larry

X-COM

pacman

Fable TLC, Fallout 1 and 2 and Wasteland.
I can't wait for Wasteland 2!

The Legend of Zelda, first game I owned.

Blip & Blop :D

Sanitarium

System Shock 2

Tetris

Shinobi (Megadrive)

I'm going with Roller Coaster Tycoon, too, like u... my favourite old game ever

I started my gaming life with platformers, and my first gaming experiences were Spyro the Dragon and Crash Bandicoot. Ah, those were the days, I'm getting all nostalgic here :)

Didnt find anyone mentioning Neverhood yet, so here it goes, i still love that game :D

DOOM.

age of empires

Age of Empires.

Scorched Earth

i would say Sonic 3

Supaplex. Still a legit game. ^^