10. Master of Orion II * Microprose (PC)
GalCiv2 will probably pass this once I get the new econ down and parameters figured out. Until then, it'll hafta sit at #11 behind a PC game I've been playing for over a decade. The biggest complaint I had about GC2 was that the races didn't seem different enough. In MOO2, you felt the difference between about half a dozen of them.

9. Street Fighter II [series] * Capcom (Arcade)

8. We Katamari * Namco (PS2)
Simple yet addictive...and you always think you can do a smidge better. The same thing that made Tetris so great, but with wacky Japanese humor. More stuff to do than in the original, which is why the sequel gets the nod.

7. Combat * Atari (2600)
The purest, and thus most fun, multiplayer game. Tanks, bi-planes, jet-planes, choppers, bouncing ammo, invisible ammo, invisible walls, invisible planes...with that much variety, I don't see how I coulda ever got bored.

6. Super Mario Bros. * Nintendo (NES)

5. Samurai Shodown II * NeoGeo (Arcade)
I always liked it better than Street Fighter II. I think it was either the anime-ness or the swords...or maybe because the arcade near me at the time had it and not SF2.

4. Final Fantasy Tactics * Square (PSX)
Still the best, most fun, RPG I've ever played. Every time I pick up an RPG, I like the parts that remind me of this game, and every RPG I find wanting in comparison to it.

3. Harvest Moon: Back to Nature * Natsume (PSX)
It is far and away the most educational game I ever played. Got me eating vegetables, cooking for myself, and drinking green tea. Story and gameplay that suck you in and full of characters I found myself being very attached to. Still playing the new HM games, but none have captured my heart like this one.

2. Super Dodge Ball * Super Techno Arts (NES)
Still the greatest arcade style sports game ever made. I remember playing this all day for weeks in three different summers when I was a kid. First video game I really geeked out on.

1. Galaga * Namco (Arcade)
Possibly the ultimate arcade game. Perfect speed. Perfect enemies. Perfect controls. Perfect sound. I just wish I were good at it.

I liked:

Homeworld (& Cataclysm), but not Homeworld2
Quake3
All Gal Civ series
FFVII
MetalGearSolid2
UT2004
SystemShock2
All HalfLife series
Oh, and PuzzleQuest.

Galactic Civilizations II(PC)
Shadowrun(Genesis)
WarcraftII(Saturn)(yea, I had it on the Saturn )
Team Fortress Classic(PC)
Deus Ex II: Invisible War(X-Box)
Earth 2150+Sequels(PC)
Re-Volt(Dreamcast)
ESIII Morrowind(X-Box)
Total Annihilation:Kingdoms(PC)
Dungeon Keeper 2(PC)

Mine of all time are: (All PC unless noted otherwise)

1) World of Warcraft
2) TESIV: Oblivion
3) Final Fantasy 7 (Playstation)
4) Civilization II
5) Half-Life 2
6) Team Fortress Classic (HL)
7) Team Fortress 2 (Pretty much a tossup between this and TFC)
8) Half-Life
9) Sins of a Solar Empire (This may move up depending on how v1.1 goes, but there's still a large rift between this and HL1)
10) City of Heroes/Villians

Some of the top 25 would be: Command and Conquer: Red Alert (playstation), Age of Empires, Doom and Doom II, Starcraft, UT2k4, Neverwinter Nights, Starfleet Command III, Freelancer, Planetside (Before the bending...) and others I can't remember off the top of my head.

10. Chrono Trigger series
9. Final Fantasy Series
8. Fallout Series
7. Dragon Warrior Series
6. Galactic Civ Series
5. Mario Series
4. Half Life Series
3. Zelda Series
2. Deus Ex Series
1. Team Fortress 2

1. Xcom(Enemy Unknown)
2. Gal Civ series
3. warcraft series
4. diablo series
5. company of heroes
6. counter strike:source
7. tribes 2
8. Civilization series
9. Halo(xbox)
10. Worms world party

Of course.  I remember playing those, and Tetris was a blast (never could get by level 10 though).

1. Descent series
2. Freespace series
3. Starcraft
4. Rise of Nations
5. Galactic Civlizations II series
6. X-Wing vs. Tie Fighter
7. Mechwarrior 4 series
8. Sim City 2000
9. Rome: Total War
10. Demonstar