One of the architects of rock guitar playing. Kind of hard to have perspective if you only vaguely know a few of his hits, but he had a massive impact on the style and sound of rock guitar. Most stock riffs guitarists learn are Chuck Berry riffs, he codified the rock blues shuffle and pentatonic box licks that Keith Richard slavishly copied and filter through to such an unlikely player as Zakk Wylde, with his piston pentatonic riffage of doom.
I listened to a lot of Chuck through my parents (My Dingaling was a campfire favorite), but I got to know Chuck when I got co-opted into our high school production of Grease. I had no clue how to play 50s rock-n-roll, so I got a couple of Chuck Berry records and began learning the hallowed riffs. I still hear echoes of that tutelage in my playing to this day.