Mozart....if only for his comment, "I write music as a sow piddles."

Lennon and McCartney, for the reasons noted in previous post.

Lenny Breau and Chet Atkins because they played guitar real good....and Manitas de Plata cause he played real good too.

Joannie Mitchell, because the list needs a female, particularly one who is and was 90% smarter than the males around her.

Richard Thompson and Mark Knofler, for their ability to paint pictures with music and lyrics.