In no particular order:
I know people will argue that Jackson and Marley don't fit into rock. I guess I just have a more expansive view of rock than they do. Also a lot of great bands Moody Blues, Talking Heads, The Doors, Sex Pistols, Fleetwood Mac aren't represented because the band is more iconic than a person in it. For those who argue the Stones and The Beatles are as iconic as Jagger and Lennon, I agree. If the list was expanded to include bands, Lennon and The Beatles would make my list as would Jagger and the Rolling Stones.