Final Fantasy 7... Its simply amazing.
Spyro the Dragon series. You have no idea the deep love I have for this series.
God of War.
Portal.
BioShock.
RBNSMTH Turok cheat for infinite ammo with all weapons. I didn't even own the game, but my friend used it all the time.
hold A+C and press up, down, left, right for sonic the hedgehog.
The first time I played Mario 64, the first time I ever thought a video game was made of pure happiness.
The first time I climbed on to a colossus and killed it in SotC. That game was made of such beauty.
In Halo 2, (on a map that i can't remember the name, but its circular and purple with a floating see-saw platform that holds a sword) I was playing it with a few friends and we were on the second level of one of the rooms with the grav-lift that shot up through the vents in the side of the room and every single person on my five person team randomly threw a sticky grenade down the grav-lift shaft and a guy from the other team flies up out of nowhere glowing blue with five stickies on his body and exploding in mid-air.
In Halo 2 when my roommate was dicking around on a snipers match and set his sights on my head and was telling me he was going to shoot, I moved forward quickly and he shot and nailed a guy on the other team trying to assassinate me.
In Halo 2 when my roommate was sitting in a room overlooking the rest of the map in a sniper match and saying how awesome he was at camping. I told him if he's going to be sitting there doing nothing, he was going to get assassinated. He said that he would bet me 20 bucks he wouldn't get assassinated because he was just too good. No sooner had the words come out of his mouth did a guy come out of nowhere and assassinate him. This story is also the story of my quickest 20 bucks i ever made.
The first time I played Halo, I became completely in love with the setting and style.