Ok here are mine:
1996: Master Of Orion 2 / Terranigma (both were amazing)
1997: Quake 2
1998: Starcraft and Brood Wars
1999: Donkey Kong 64
2000: Majora's Mask
2001: Diablo 2: Lord of Destruction / Smash Bros Melee (both were amazing)
2002: Metroid Prime
2003: Sim City 4
2004: World of Warcraft...