Oh man, this would be great. Me, I don't just want one kind of music; I want to form a band that can play any conceivable type of music, like a sort of "variety band." Some of these people aren't real, but they've demonstrated sufficient musical talent to warrant inclusion in a supergroup in a thread that's already removed a restriction on including deceased musicians.
Vocals: Noriko Mitose, Elton John, Marshall "Eminem" Mathers, James Marsters
Guitar: Jimi Hendrix, Nobuo Uematsu
Bass: Link
Violin: Yo-Yo Ma
Cello: Shinji Ikari
Piano: Ray Charles
Organ: Johann Sebastian Bach
Sax: Weird Al Yankovic
Drums: A couple of guys I know from high school; All-Staters and awesome guys in general.