I'm gonna have to go for the 9 year old, Freelancer.
It was like playing Elite, for the 21st Century.
Although a little formulaic, in gameplay and without the open-endedness of Elite. Still a game that I go back to time and time again.
On the PC - Frontier Elite II, GTA Vice City and Age of Empires 2.
I saw a screenshot of Strykers Run in a book yesterday so I fired up Beebem for that!
I keep returning to GTA4 on the PC atm - for some reason there's a lot of fun to be had mowing down the fat bikers outside the Burger Shot on the road to the airport.....
Donkey Kong Country on the SNES was quality as well as the first Syphon Filter!
I remember being hooked on that stayling awake long in the night instead of revising for my exams to clear a level and save it on my memmory card!
Also Street Fighter II Turbo on the SNES.
As you can imagine - I love the SNES! Quality piece of gaming console
To me, a game just doesn't feel old unless it was made before 2000...
Personally the first C&C (ah the guard tower cheap infantry trick/ cheat...) and Crusader: No Remorse were responsible for eating up most of the late 90's for me.
I rediscovered Jonah Lomu Rugby quite recently, oh how I miss Bill McLaren's commentary .
The original Red alert, Dungeon Keeper, RCT (rollercoaster tycoon) + add on packs and theme hospital were the games of my youth, still play them now and then today! :)
Oh and I loved The Incredible Machine
This screenshot isnt the original tho :(
*May contain traces of fibs.
Anybody remember the "Stunts" car game? http://en.wikipedia.org/wiki/Stunts_%28video_game%29
Ah well, if we're talking degree ruiners, a combination of Rome: Total War and Halo 2 did for mine :p
UFO: Enemy Unkown (X-Com: UFO Defence for those over the pond)
I played Dreamweb again the other day and even found online a pdf of diary of a madman which has clues for the game in it.
UFO/X-Com games - this basically killed my studies at school!