Well, I'm gonna go a different route. One that I always take with my fantasy baseball teams too. I love the multi-positional guys, so I'm gonna go with a bunch of multi-instrumentalists here, who all happen to be incredible songwriters and vocalists from different eras and/or genres, to allow the band to touch on nearly all styles of music.. While limiting their labeling to "main instruments", Piano and other assorted instruments will also be available to my "fantasy band". The fact that most members play all instruments, will also allow them to fill in any gaps and make up for any stylistic shortcomings of the others in the songwriting process. There will also be a lot of "natural variation" in vocal styles and tones, to create nearly unheard of harmonies..
Guitar 1: Prince(great guitar player, vocalist, songwriter, played all instruments on first 5 albums, reportedly plays 27 instruments).
Guitar 2: John Mayer(I'm not even a fan, but he is a pretty good songwriter, solid vocalist, and one hell of a guitar player)
Bass:Paul McCatney(jack of all trades, great vocalist and songwriter)
Drums
ave Grohl(jack of all trades, great vocalist and songwriter)
Vocals:Mike Patton(possibly the most diverse vocalist ever, can sing multiple languages and styles. Probably one of the best at using vocals as an instrument, also great with electronic programming)
Alternate guitar player:Phil Keaggy