1. Final Fantasy VI
This is the pinnacle of the SNES trilogy in my opinion. The story is fantastic and the game play is great.
2. Metroid Prime
This is one of the most atmospheric games ever created and easily the best game cube game available.
Diablo is the first multiplayer game that I really got into. The sequel was also good but it doesn't have that special something that the first game had.
4. Final Fantasy IX
This is my favorite in the whole series, It took on an older school FF look and feel which has some awesome Easter eggs that die hard FF fans will notice which is great.
This game has, in my opinion, the greatest story ever in a videogame. Like other games of its time its starting to show its age. However the story and challenge this game offers is fantastic.