SNES - A True gamers console. The golden age of 2D gaming, there were such unbelievable gems on SNES like there have never been on any other console.
Gamecube: I only had this and a PS2 last generation, but this console had a ton of brilliant games that I couldn't get anywhere else, it was lightwieght, portable and had the best controller. I have 40 games and plenty more that I couldn't actually afford.
Gameboy Advance/ DS: Seeing as you can play GBA games on DS you would think I would just put DS here, but some of the best times I got from my GBA was playing multiplayer games with friends. Some really really brilliant games, not to mention Golden Sun, which shits all over almost any Console RPG, even most of the Final Fantasy series.
PS2: This console really deserves a mention, it really is a Fighter fans and an RPG fans dream, plus some really great niche games like ICO were released for it. I have some issues with this though, it was underpowered, overpriced and broke down too fucking often.