1. DOOM - For me the best game ever, the first game I saw and reminds me of the good, old, funny times
2. Heretic - I really loved to play this with my brother and parents 😁
3. Hexen: Beyond Heretic - I loved to play this with my best friend
4. Midtown Madness - I enjoyed it every time
5. Diablo2 - Really enjoyed it and found some nice friends during playing it on Battle.net
6. Age of Empires 2 - Fun for the whole family 😁
7. Blood - I like this game ^^
8. Quake III Arena - Even today it's still great fun on a LAN-Party
9. Turok: Dinosaur Hunter - I loved dinosaurs when I was a little boy
10. Jazz Jackrabbit 2 - For me the best game I've ever played on Win95 ^^
11. Serious Sam: The First Encounter - very funny game and reminds me of the best times with the best friends
12. Tuneland - Really loved this one when I was about 4 years old

PC Games only and in no specific order:

Wolfenstein 3D - The Classic FPS, one of the first games I toss on a old PC to play.
X-Wing - Another one of my youthful favorites.
Skyroads - A simple DOS Casual Game from before "Casual Game" was even a term.
Unreal Tournament - All time favorite LAN game. This was a LAN party staple for me all the way to 2007.
Quake II - Probably my favorite all time FPS.
Winroids - A simple Win3.11 Asteroids clone that came on my Bravo Sound 16 CD. Addictive.
X-Wing vs Tie Fighter - I always thought this was awesome, and you could loana friend Disk 2 and play head to head via Modem.
Need for Speed IIse & Need for Speed III - My all-time favorite racers.
Duke Nukem 2 - Great classic platformer
Worms - Spent many of hour playing the DOS version.
Redneck Rampage - C'mon, any game that uses Whiskey and Pork rinds for health pickups has to be good.

Good choices. My personal list would be:

1. Doom - downloaded at college and had awesome deathmatches
2. Either Tie Fighter or X-wing v. Tie Fighter - needs no explanation 😀
3. Quake 2 - First "modern" FPS I played
4. Syndicate (or Syndicate Wars) - what's not to love about killer cyborgs?
5. MS Flight Simulator of appropriate vintage - infinite replay value
6. Falcon 4.0 - infinite replay with weapons
7. Eye of the Beholder - classic RPG
8. Pool of Radiance - first RPG I ever played
9. Pools of Darkness - end of series that started with Poolrad
10. Diablo (or Diablo II) - Hack and slash, good replay
11. Ultima 7 w/ all expansions - epic RPG
12. Baldur's Gate or Neverwinter Nights (although NWN came out in 2002 so that would be a bit of a cheat - I would love to have BG 1 and 2 but technically that's 2 games) - anyway, BG 1&2 have excellent story, good combat, nice graphics for the era. NWN would let me make adventures.

I guess if I could squeak NWN in I would get rid of Pool of Radience and Pool of Darkness to fit BG 1&2 in. If I can count BG 1&2 as 1 game I would ditch Pools of Radiance

Crusader No Remorse or Crusader no Regret would be good runners-up.
If I had room for more, Fallout 1&2 and Planescape Torment would surely be in there. I might have to rethink my list - Torment is a classic 😀

For PC only I assume. Some I haven't finished but remain burn in my mind as need to play!

1 Rocket Jockey > Never gets old and the style never has been duplicated
2 Carmageddon 2 > GTA without the story. Great for chillin out
3 Shadow Warrior > Who want some wang?
4 Redneck Rampage > Theres alot of these and never finished any of them!
5 Neverhood > My avatar is from Neverhoods sequel 😀
6 Grim Fandango > Like many of these games it draws me in although I never finished it
7 POD > A great 3Dfx game for its time
8 Quake > THE game changer for 3D
9 Need for speed 3 Hot Pursuit > Almost a tossup with NSF4
10 Star Wars Ep. 1 Racer > Not a fan of star wars but like the game alot (sequel not so great 🙁 )
11 Twisted Metal 2 > its on the PC so it counts!
12 Blood 2 > Always want to play it but never finished like half my list

Yes, i'm a slacker!

For PC:

Operation: Inner Space
Theme Park
Theme Hospital
Dungeon Keeper
Lands Of Lore The Throne of Chaos
Heroes of Might and Magic II
Heroes of Might and Magic III
Zombie Wars
Discworld
Unreal Tournament
Simon The Sorcerer
Gearheads

Why? Because they're all great games and these are amongst my favourites.

I'd only take games that I haven't started or finished yet. Like outcast, giant, b&w ...

Any Ultima game, but especially III and IV. The series really peaked with those two.
Grim Fandango
Any Star Wars game released during that time period
Anything by id software
Diablo
Any Dungeons and Dragons licensed game by SSI
Any Dungeons and Dragons licensed game by Bioware
Any game with The Elder Scrolls in the title
Betrayal at Krondor
Myst/Riven
Anything by Infocom
Civilization/Colonization/Alpha Centauri

only 12... hard decisions...

1. The Ultimate Doom
2. Duke Nukem 3D Atomic
3. One Unit Whole Blood
4. Age of Empires 2 + The Conquerors
5. Sam and Max Hit The Road
6. Outlaws
7. Monkey Island
8. Tyrian 2000
9. Baldur's Gate + Tales of the Sword Coast
10. Half-Life + Opposing Force + Blue Shift
11. Quake + Scourge of Armagon + Dissolution of Eternity
12. Command and Conquer Red Alert

Well, since some of you mentioned some of my favourite games (the role playing games by SSI and Bioware) and the HOM&M, then if we see them as "one game package", then I think you could squeeze in the game compilations of the RPGs and the HOM&M games. And what not, if there are other nice and great game compilations 😀

1. Starcraft
2. Star Control II
3. Starsiege Tribes
4. Command & Conquer Red Alert
5. Quake III Arena
6. Jagged Alliance 2
7. Doom II
8. Duke Nukem 3D - Thank you "43980 levels" shovelware!
9. Quake - progs106.zip and qtools.tar.gz are a lifesaver
10. Jetpack
11. Unreal Tournament
12. Freespace 2

Errmmm...I'm confused... is this list about

- what I WOULD LIKE to get in future?

or

- my FAVOURITE games-of-all-time list?

or

- games that CHANGED me?

or

- games that IMPRESSED me?

And may I ask why the number 12? - Usually questions like these come in the "Top-10" or "Top-5" flavour. 😁

I've collected almost all of my favourite games, complete with boxes, except a few.

Anyway, what I REALLY WANT to get are :

1. Worlds of Ultima - Martian Dreams. I and my buddy completed this without the help of any external hints or walkthroughs back in 1991. We only communicated via phone and in our classroom at high school to exchange our progress in the game.
The one available at ebay now is a bit too expensive, even for a collector like me.

2. Wing Commander Kilrathi Saga - would like to have a complete boxed edition, like Kreshna has.

3. F-29 Retaliator by Ocean. I was only able to get the Amiga version, which is fully boxed with manual (even though I do NOT own an Amiga!)

4. I've been looking for a copy of Low Blow by Electronic Arts. - A funny boxing game.

....that's all I can remember for now......

Diablo 2
Giants: Citizen Kabuto
NFS: PU
Dungeon Keeper 2
Age of Empires 2
Caesar III
Sim City 3000
Star Wars Ep 1 Racer
System Shock 2
Pharaoh
Quake 2
NOLF 1

Frederick Pohl's Gateway
Quest for Glory I
King's Quest VI
Robinhood: Conquests of the Longbow
Grand Theft Auto I
Master of Orion
Civilisation
Frontier: Elite II
Betrayal at Krondor
Elder Scrolls II: Daggerfall
Mean Streets
Sim City 2000

In response to Malik, its more like your top 12 favorite games that if you were leaving all else behind to go to an island commune (or interstellar voyage or what have you 😀 ) that you would absolutely have to have.
Also, a brief blurb what you liked about them.

As far as to why 12? It seemed like a good number. 5 is too few (that would be really hard to choose a top 5) Top ten I suppose would work as well, but I had a hard time with 12.
I suppose I could have put no limit or a higher limit but it gets really easy to say "hmm probably should put this on there too" 😁

If this was just relegated to pc games only, up to 2000, my list would be:
Doom 2 (never played all the way through)
Quake 2 (never played all the way through the add on pack)
Shogo (played all the way through, would love to again)
Rollcage Stage 2 (game speaks for itself)
NFS: High Stakes (game speaks for itself)
Mega Race (a deserted island with no Lance Boyle would be lonely indeed)
Primal Rage (arcade fix)
Mortal Kombat 3 (arcade fix)
Street Fighter Alpha 2 (arcade fix)
Darius Gaiden (arcade fix)
Fallout (never played all the way through)
Dune 2000 (never played all the way through)

Halloween Harry (favourite apogee game, great graphics and music)
Heroes of Might and Magic 3 + expansions (awesome strategy game, best in series)
Sid Meier's Alpha Centauri + exp }
Civilization 2 } I love Sid Meier's turn based games and these are his 3 best 😀
Colonization }
Caesar 3 (favourite city building game)
System Shock 2 (best FPS ever made IMO)
Master of Orion 2 (another great strategy game)
Sam and Max Hit the Road (favourite Lucusarts edventure... the jokes never seem to get old)
Transport Tycoon Deluxe (another brilliant strategy game)
Stunts (aka 4d sports driving... great driving game, with track editor for unlimited replayability)
Tie Fighter DOS CDROM (best star wars game ever made... awesome space shooter)

As you can see I really like strategy games 😀

Oh I see, in that case, here's a list where I can just play again and again without getting bored :

1. Gods - No matter how many times I play this, I never get fed up. The timings for certain puzzles, hidden bonueses and more keep me trying to get all again and again.

2. Prince of Persia 1 - A timeless classic. I don't mind playing again and again.

3. Diablo II + LoD Exp. - Immense replayability.

4. Wing Commander Kilrathi Saga - Has all my favourites and has updated cockpits for WC I and II.

5. Ultima VII Complete - "If you can see it, you can do something with it" .

6. Doom II - Gimme that double-barrelled shotgun!!

7. King's Quest V - Absence Makes the Heart Go Yonder - I have a special attachment with this game - the music and Sierra's first 256-coloured VGA adventure game. Most of the time, I just keep listening to the music.

8. Secret of Monkey Island & Monkey Island 2 - White Label Collection CD. - Has both of my all time favourites. Mostly I play them to listen to the wonderful music, though. The CD also contains Secret of Monkey Island's music in audio CD format.

9. The Krynn Triligy - Champions, Death Knights & Dark Queen of Krynn. - I was more attached to the Dragonlance series of the SSI's TSR AD&D games. And the ability to carry on with the same characters from the first to the third game.

10. Desperados - Wanted Dead or Alive - the first game has surprisingly addictive gameplay. And the fusion of "Tactical Team Based Strategy" game in a Wild Wild West setting is unmatched. Great music too! The sequels don't have the same appeal.

11. Wages of War - The Business of Battle. - Continuous missions.

12. Crusader No Regret. - Blasting everthing that you can see has never been this fun. Add in the much appropriate tune and it's time for a blast.

Oh, and I would love to take my CM-500 too, with these games.

1 bubble bobble
2 resident evil/biohazard
3 alone in the dark
4 golden axe
5 double dragon (arcade)
6 bio menamce
7 the chaos engine
8 mad cars
9 microprose soccer
10 rastan
11 xargon
12 time gate: knight's chase

it might change through time and moods

Lords of the Realm II -> this game just makes me feel warm inside
Diablo II -> replayability
Carmageddon II -> played for hours & hours, but never beat it
Dungeon Keeper II -> DK1 would suffice too, still waiting for DK3...
Baldur's Gate II -> loved the 1st but never played the 2nd...wierd
Railroad Tycoon II -> I like trains
Civilization II -> haven't played in so long, but was like crack back in the day
The Elder Scrolls II: Daggerfall -> never played it but damn I love me some Oblivion, Fallout 3 & Skyrim
Command & Conquer: Red Alert 2 -> need a RTS in here, wow been over 10 years since I played this
Unreal Tournament -> cause I can't put Unreal Tournament 2004 here
Age of Wonders -> maybe one day I will replay and beat this game
Ceasar III -> I need a city builder in here, would prefer Anno 1701 though