I was at a party where people were playing Guitar Hero and SingStar last night.  That got me thinking about the possibilities for Wii Music, if the game combined vocals with motion controlled instrumentals.  (Not as cool as GH or Rockband, but without the expensive perfs)  Plus Mii integration would also be a big draw I think.

Could it be the next big killer-app casual game? 

wii music could turn out to be really well and i hope it does

Will sell 2x the install base of the Wii on the first day.

If it has "Wii" on the title like Sports, Play, Fit; yes, it will sell millions.

Actually I think an WiiArt should include a mario paint type of game and music as they are both art.

^that would be good

 QFT~

good idea,but how would it work?

 It would come with a pair of mic attachments for the end of the WiiMote.  Simply hold the WiiMote like a microphone. 

They should allow you to load music off of an sd card and make your own sheet music for it.