Young students of rock guitar don't always have the gift of perspective. I remember in the early '90s hearing a fine young player, who worked at a great recording studio, tell me "I don't get what all the fuss is about Hendrix".
For this kid, the root player of his youth was Edward VanHalen, and he grew up hearing the acrobatics of the following generation. And while Mr. VanHalen is indeed a fine player, the family tree goes much further back.
The reality is that most modern rock guitar is shaped in large part by one guy, Eric Clapton. When his playing first made it to the US, first in the Yardbirds, then in the stunning John Mayall & The Bluesbreakers album, players all sat up and took note: this guy had moved the bar much higher. While not that far removed from other good players of the day, Clapton had a fluidity and lyricism no one had shown before. He could play a solo that was wall-to-wall notes and never repeat the same riff, nor give you the feeling that he was even playing riffs, just the flowing arc of a sonic story.
Smart players have scrutinized Clapton's roots, invariably landing on Buddy Guy, likely the best of the '60s Chicago guitar slingers. And today, at age 72, Buddy is still tearing it up.
But we have to look further back to find the real root of modern rock guitar, back to 1942, when a young man named Aaron Thibeaux Walker recorded "Mean Old World" for the new Capitol Records:
T-Bone Walker took earlier, more primitive blues guitar styles, filtered them through the jazz stylings and electric guitar of Charlie Christian, added horn-like phrasing, and became the real root of today's rock guitar.
Here he is with some minor jazz musicians* in '66:
T-Bone could also write a song, too. Here he is singing "Stormy Monday", covered by about 1000 other artists, which he wrote and recorded in 1947:
Oh, and guitar players, did you catch his signature flamed blond ES-5, with P-90s? It's an early specimen, from '49-'54, with no tone controls, just individual and master volume knobs. More on it and other Gibsons here: http://www.provide.net/~cfh/gibson3.html
* Dizzy Gillespie, Teddy Wilson, Louis Bellson, Clark Terry, Coleman Hawkins, Zoot Sims, Jimmy Moody, Benny Carter and Bob Cranshaw.