Bob Dylan
Neil Young
John Lennon
Tori Amos
Ray Davies
Honourable mentions-
David Bowie
Pete Townsend
Kate Bush
Jim Morrison
You edited this, right? You had McCartney on there; not sure whether you're right to remove him or not, given his (Beatles) back catalogue. It really does seem that there was something about his (songwriting) relationship with Lennon though (even though I don't mind Wings [sort of!]).
Not totally sure about Morrison - think he was a ***** too, but maybe that goes with the genius bit (I like the Doors btw). His poetry gets well rated (on programmes about Morrison); however, whilst I'm no poetry critic, I'm not totally convinced. I think what sometimes gets buried in the 'legend' is his anti social control stance - trying to get people (audiences) to think (which was what caused so much problem with the 'authorities' [because he had a big a. Bowie was, arguably, a genius at adopting other people's ideas and making something more of them (but that's the nature of much art so, fair enough).
Oh yeh, you removed Roger Waters; he'd been in the back of my mind but I'm not sure the genius epithet applies (although, given that he was the primary lyricist and driver of much of Floyds best work....).
Jimi Hendrix has been mentioned, right....?