Metroid Prime, Resident Evil and Resident Evil 4.

Most of the Nintendo franchises that impressed me the most on the N64 were a disappointment on Gamecube - Wind Waker was worse than Ocarina of Time, Mario Sunshine was not as good as Mario 64, Mario Kart 64 was better than Double Dash!! and Starfox Assault was a bit lame.

Metroid Prime, period. As much as I enjoyed that system, it's games were pretty much watered down N64 titles. Sunshine wasnt as innovative as Mario 64. Wind Waker wasn't as innovative as either OOT/MM. Double Dash wasn't the leap forward that MK 64 was. That's pretty much why that system failed so badly.

The only exceptions were Melee, Pikmin and Prime. Prime was my favorite out of those three because it was so immersive, serious and gritty. Exploring the world as Samus was such a joy and Retro nailed it.

SSBM

It's got to be Smash Bros. for me. I played that game like it was my job.

So many amazing games but Killer 7 is mine. Took me so long to get and then play it and when I beat it I felt so amazed by it. I just played Eternal Darkness a couple months ago and that game is a horror masterpiece in my eyes. Lots of great games I have and still need to play on that system. Gaahhhh to many good games.

I've not played many but from the 4 I've played my favorite is Tales of Symphonia, because the characters and their interactions are great (my favorites are Sheena and Raine) and the story was so motivating, the battles were fun.

Second place would be The Wind Waker, it's pretty fun and I love the sidequests.

GC was awesome. Plenty of great games but my fave was SSB Melee. I put more hours in that game than all the PS2 games I played collectively, and I owned well over 300 PS2 games. Fun game ...

Metroid Prime once in a lifetime experience atmopshere is something no movie can replicate also RE4 and F Zero GX.

Metroid Prime/RE4/Twilight Princess

Ironically, all three came to Wii and were even better for it.

I never had GameCube but if I had I'm sure it would be SSX3 =D