Probably these:
1. Starcraft, the gameplay, the customs, the music, the storyline, the fact it was all tied together in 1998 much better than many games today are is fantastic. Starcraft II is great as well but it has still to prove itself.
2. Half life 2, so much fun with such a cool storyline, a rare combo.
3. Dead space, this is survival horror done right, very cool game! Resident evil is dead to me.
4. Resident evil 2/3, scary games with cool monsters and storyline, lengthly as well, especially 2.
5. Farcry/Crysis, excellent mix of run and gun plus optional stealth, farcry was something special in 2003 and crysis built on that.
6. Alpha Centauri, what a frickin weird game i thought when i first played it, i built lines of what i later learned were sensor towers thinking they would be like the obelisk of light from c&c 1 only to be stunned when enemies walked right past them. Also being able to capture forests seemed weird, i later learned that was the gaian factions bases heh. Had many fun games on this over the years and it was and still is better than civ imo.
7. Fallout 3, i never played the first two fallout games but i had played oblivion and didnt like it all that much. I enjoyed battering the townspeople with a sword and stealing from them but that got old fast. I also played stalker but its engine was rubbish the loading between areas was a PITA and the whole game was a bit of an overcomplicated drag tbh. I always thought it would be cool if they remade oblivion with guns in a nuclear wasteland setting which is what fallout 3 is, amazing game!
8. C&C RA1, Spent a lot of time playing this, fighting giant ants etc, very cool game, great music, great storyline, great gameplay, the only thing it lacked was a good online component such as battle.net, if it had that i believe people today may still be playing it. Hell theyre still playing RA2.
9. Diablo II, Oh man, talk about addictive... Must farm must get more SoJ's to buy awesome items to dominate everyone else, then maybe build a new char and get awesome items for that and so on. Such a fun game shame blizz wrecked it with 1.10. Only thing blizz have screwed up IMO.
10. Giants citizen kabuto, Funny game with cool story/characters and great gameplay. Online was a blast as well!
11. Recoil, The first and best tank sim ive ever played. Dunno if its really a tank sim, its more of an FPS where you happen to be a tank which can shoot lasers/fire/ice/mortar/electricity/mines/missiles/nukes and can also transform into a hovertank/boat/submarine. Easily i might add, which is what made it fun for me
12. Simcity 2000, awesome fun!
13. GTA 1, i actually contemplated having my friend copy it onto about 40 floppy disks so i could play it at my house, it was so fun and i couldnt wait till my birthday to get it.
14. Star trek armada II, it was just really fun, had everything i wanted in an RTS at the time along with cool sci-fi stuff
15. Star trek elite force, great game, cool story, fun levels and gameplay. Only bad thing about this is not being able to go on a rampage and take over voyager single handedly. If you try your character will drop to their knees and cry after killing 2-3 crewmates which ends the game, sucks.