37. Bo Diddley
Diddley's beat was as simple as a diddley bow, the one-stringed African instrument that inspired his nickname. But in songs such as "Mona," "I'm a Man" and "You Can't Judge a Book by the Cover," his tremolo-laden guitar argued that rhythm was as important as melody, maybe more so. Born in Mississippi, he grew up as Ellas McDaniel in Chicago, where he studied violin and learned how to make both violins and guitars. His late-1950s singles on Checker could be both terrifying ("Who Do You Love") and hilarious ("Crackin Up"). The sounds he coaxed out of his homemade guitar were groundbreaking, influencing just about everyone in the British Invasion.