XBox and PS have hype, but they lack innovation. They're just PCs in fancy packaging. Nintendo has always been about the brand and experience. Create fun games most people (apparently not sezyboy) want to play. The new controllers, the "get off your ass and play" philosophy, its all something Nintendo banked on, while Microsoft and Sony were just putting fancier graphics without any change to the gameplay. XBox and PS3 appeal to hardcore gamers, Wii appeals to families, couples, grandparents, kids, a much wider range.
No, it hasn't always worked for Nintendo (virtual-boy, power-glove, etc...), but its good to see them back in the game. After the Gamecube, it was looking a little iffy for them (not that Pokemon alone couldn't keep them afloat if necessary).