There were many I'm going to list the ones I played the most.
On my N64 it was Mario Party, Legend of Zelda Majora's mask an Ocarina of time, Kirby 64 and F-zero X played them so much my N64 actually burned!
On PC StarCraft, Age of Empires and Maple Story which was my first MMORPG but I stopped liking MMORPGs recently now I just find them boring and think how could I have spent so much time in Maple Story?
And on GameCube it was Time Splitters 2 and Future Perfect, Metal Gear Solid The twin snakes (even though I didn't knew english when I played this I still liked the videos) and Wind Waker.
And those were the games I played the most.
Edit: Oh I almost forgot I played Super Smash Brothers Melee to death I probably have full years of playtime accumulated for that thing in fact I still play it from time to time!