I can't believe Elvis sold that many albums. The Beatles I completely understand. Their music is timeless and influential. I have a hard time coming up with more than 4 or 5 Elvis songs. I think time has been kinder to the Beatles music over Elvis.
Sidenote to what you said (the timeless / influential part), but Elvis is rather underrated as a singer (and frankly his influence as a performer) these days because his style has been so parodied that I think people don't realize that he was actually really good. He's no Jackie Wilson, but the guy had some serious pipes.
And this reminds me of this post. Some of the videos are down now, but since they come from the studio versions it oughtn't be hard to find them.