The Wii is, at least to the generic public, a very multiplayer oriented system. You can't enjoy the flagship Wii Tennis without a second controller ... oh, wait, we need a nunchuk for boxing as well ... but man, three-player would be so cool! And so on and so forth. But Wiimotes are frakkin' expensive. Forty for the main, twenty for the add, you know the deal.
Sooooooo, where did you draw the line? Did you pick up an extra Wiimote with Wii Play? Do all of your Wiimotes have nunchucks? Did you drop the hundred and eighty dollars for the full complement, not including any Classic Controllers? And for the love of God, use rechargeable batteries. Mother nature and your wallet will thank you.