It had my favorite Smash Bros, my favorite Mario Kart, my favorite Zelda, and Sunshine, which is tied with 64 as my favorite 3D Mario. Really hard to choose. I'll say Smash since that was probably what I put the most hours into.

Metroid Prime. I was strictly a PC gamer until that came out. The atmospheric world, the original, responsive 60FPS gameplay. It was amazing.

Now I'm basically a PC & Nintendo gamer. But I also like Naughty Dog as a developer and the only way to play their games is on PS.

Metroid Prime, Resident Evil 4.

Luigi's Mansion, really loved the atmosphere in that game.

Resident evil REmake and zero, because they were the best part of the series, old classic resi with updated graphics

Paper Mario: Thousand Year Door squeezes in as my favorite Gamecube game, but there are quite a few that came close. Tales of Symphonia, Super Mario Sunshine, and Baten Kaitos: Eternal Wings and the Lost Ocean really sucked me in, too.

Really hard to pick just one. I loved Super Smash Bros. Melee, Mario Kart Double Dash, Resident Evil 4 & REmake.. there were plenty of great games on that system. :)

BATEN KAITOS: Eternal Wings and the Lost Ocean, and Baten Kaitos Origins! Can't believe anybody named those! AMAZING games!

Legend of Zelda: Twilight Princess.

Though I played it more on the Wii, I still consider it a GameCube game. That was also the first version of the game I got. Twilight Princess is one of my top 10 favorite games of all time, and probably the only GameCube game I'd consider a 'classic'. It looked stunning for it's time, but it also had superb gameplay, and top notch level-design.

Besides that the only other games on GameCube that were 'very good' in my book were Luigi's Mansion, and Legend of Zelda: The Wind Waker. The remake of the latter on WiiU is loads better though and both those games are leagues beneath Twilight Princess. Note, I've never played Metroid Prime, which by the looks of it, I should. Of the big games on the system Mario Sunshine and Mario Kart Double Dash were disappointing to me, and I've never been a huge fan of Smash Bros. to begin with. I've only played Resident Evil 4 on Wii.

Resident Evil 4
F-Zero GX
Metroid Prime 2: Echoes

These would be my picks.