Chuck Berry and BB King are conspicuously missing, as are other groups like the Temptations. All had key roles to play in this rock-and-roll journey.

However, imho, no doubt it is Elvis. Sure, Ol' Blue Eyes was a crooner, and the best of his generation, but if we're talking about pure influence and impact on the musical genre, then by far and away, Elvis blended the negro-rock of the time with his Gospel voice, making the exclusively black music acceptable across racial lines.

A close second would be The Beatles, since obviously they're impact is overwhelming. But Elvis made rock-and-roll, well, rock.