As much as I love Elvis, I'd go with the Beatles.
Elvis had a singular talent for singing, dancing, and being a heart throb.
The Beatles had those as well, with talents for writing, philosophy, longevity and evolution of style in addition.
Elvis revolutionized by bringing rockabilly and gospel to the national stage, but the Beatles blew the music scene to smithereens, and seeped into the national conversation on all fronts, philosophical, political, fashion-wise, etc.
I've got a real red wagon!!