Wii system accessories- what are must-have items?

[Lottery Larry]

I'm planning on getting a system for my young kids (10, 7, 6).

What accessories (besides the wireless controllers) do I HAVE to have? I'm questioning the nunchunks and other things, such as the recharger.... along with how many of each extra item I need to buy, for most efficient usage (playability and ROI)

Games, I'm not overly worried about. They should be simple enough to add over time.

Thanks