Following MX's lead I'll go strictly with current and last gen systems. Heck, I'll even go in the order I got'em: PS2, Gamecube, XBOX, Gameboy Advance, DS, Wii, 360, and PS3.
I've played the Wii most of this generation simply because of Brawl, but I do disagree with Shrooms to an extent. Games like Zack & Wiki, No More Heroes, and Super Mario Galaxy (total classic) are fantastic single player experiences that exemplify how much potential the Wii really has if you put in the effort. That said, the Wii's library is definitely lacking because most developers seem to assume that as long as it's on the Wii it'll sell like hotcakes.
While we're at the system listing game, lets list our favorite game for the systems we have, too!
PS2: Shadow of the Colossus
XBOX: Halo 2
Gamecube: Legend of Zelda: The Wind Waker (I'd say Super Smash Bros. Melee, but that seems redundant with me mentioning Brawl in the next line)
Wii: Super Smash Bros. Brawl
360: Mass Effect
PS3: Metal Gear Solid 4
GBA: Really I only bought one to play Four Swords on the Gamecube with some friends, but I do loves me some Mario & Luigi
DS: Currently it's Pokemon Pearl, but I still have yet to play Phantom Hourglass