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.
SNL Standards and Practices - "you can't say 'midget,' It's just like saying the N-word.'
John Mulaney - "No it isn't, because you JUST SAID midget."