GameCube to this day, is still the largest collection of games I have for any system I own. By far. Wii is probably second, then N64 is third, PS2, Xbox 360, etc.
GameCube had so many good games...
SSB Melee, Double Dash, Sunshine, Metroid Prime, Eternal Darkness, TTYD, Wind Waker, StarFox Adventures, Pikmin 2, Rogue Squadron 2 & 3, Viewtiful Joe (before it went multiplatform), and RE 4 (same)