My hubby and I LOVE our Wii. We mostly play Wii Sports and Guitar Hero 3. He plays Mario Galaxy and Zelda as well, but I prefer the short games. The only accessories we have are an extra Wiimote and Nunchuck and the Guitar that came with Guitar Hero. We'd love to have another guitar so we could play at the same time, but we haven't wanted to spend the $30-$50 to get one yet. Maybe soon.
I'd also really love to try Wii Fit.