Actually, Buddy Holly was inspired to become a rock'n'roll artist instead of a country artist (which is what he originally was) because of seeing Elvis Presley at the gig in Lubbock, Texas in 1955 (
there's video of this). In fact, Gene Vincent got his career by winning a radio contest to find the next Elvis (notice the vocal similarity on Be-Bop-A-Lula). A lot of people were inspired by and got into music because of Elvis.
And his inspirations were hardly just Crudup and the like (that's the biggest misunderstanding of his early years). The first artist he wanted to be like when he came to Sun Studios was Dean Martin, of all people. One of his early desires was to join a gospel quartet. Ballads and gospel were foremost in his heart. But that's not what Sam Phillips wanted (he was a blues guy). Eventually, after months of recording ballads, Elvis broke out with That's All Right on a break and gave Sam what he was looking for. You'll notice that when Elvis was given free reign to record what he wanted, ballads take up the majority of his recordings. At home in private, it was gospel that he sang and played on the piano the entire night.
Elvis made his first recording in August of 1953, by the way (My Happiness / That's When Your Heartaches Begin)--a $4 acetate recording.
Though his blending of blues, country and gospel wouldn't come until July 5, 1954, of course (That's All Right / Blue Moon Of Kentucky). That's All Right was called too country to be blues and Blue Moon Of Kentucky was called too bluesy to be bluegrass. That was the BIRTH of rock'n'roll.
The most popular preconception is that rock'n'roll is just jump blues, when it equally borrows from country, gospel, bluegrass, pop, opera, boogie-woogie, Dixieland jazz, folk, etc... as much as the rural blues. The mixture of styles is what makes it rock'n'roll. Of course, rockabilly is possibly the most pure form of this original concoction (and Elvis did invent the rockabilly stage of it), but it expanded so far that all sorts of musical subgroups were included under "rock'n'roll", even if they weren't like the original Sun Records stuff.
My next favorite artists after Elvis Presley are Wolfgang Amadeus Mozart (I'm a huge Mozart nut, too), Jerry Lee Lewis, The Righteous Brothers, The Platters, etc...
But yeah, the '70s ballad-singing, introspective Elvis is my favorite. That's when he was the genius of emotion.