I was keeping it narrow to American rockers. You start throwing Brits in and you've got the aforementioned Waters, and Lynne, plus the likes of Bowie, Townshend, Jagger, Clapton, etc... and suddenly I have trouble putting Shaw in the top 20.
Yeah, as I was typing those names in, it became obvious it was mostly artists from across the big pond. But, I gotta tip my hat to those blokes. They make some great contributions to the music industry. And though they get mixed reviews on here, I'm have the greatest appreciation for the Fab Four. Hell, while I'm at it, I'm also a huge fan of Cat "Yusuf Islam" Stevens.