So many to choose from...
1- Metal Gear Solid: when i got my ps2, the first game i wanted from the old playstation back catalogue was this. My previous console was an N64, so this world of FMVs and speech was new to me. I still look for this game in shops for one last bash.
2- Ocarina of Time: after so much waiting, after all the delays and hype, finally playing it was immense. What a game.
3- Pokemon Blue: im surprised nobody said any of these games. This dominated my life for a while, as i just HAD to get my team of 6 Mews up to level 100. Go Pikachu!
I hope my 360 doesn't RRoD
"Suck my balls!" - Tag courtesy of Fkusmot