For those of you who do have a Wii, what components would you get/which controllers and games do you get the most use out of?

We may be doing a big Wii Xmas. My parents normally give us $600 each Christmas and I was thinking about getting the basic bundle package, mario kart, and guitar hero (my 7 year old daughter loves the one her cousin has) and an extra controller or two. Any feedback?

Thanks in advance for your help,

Jen