My favorites:
“Maybellene” Released, 1955
Buddy Holly Gives America a Strat Attack, 1957
Bo Diddley Delivers The Beat, 1957
... although, from what I've heard, the "Bo Diddley Beat" story is mostly bullsh*t.
"I got my beat when I heard [Gene Autry's] '(I Got Spurs That) Jingle Jangle Jingle,' " Diddley said Monday from his home outside of Gainesville, Fla. "I heard that on the radio on the South Side of Chicago. I was 7 years old."
http://www.suntimes.com/output/music/cst-ftr-bo05.html
I liked this one as well. I can imagine people sitting down watching the Ed Sullivan Show and wondering what on earth is that strange-looking contraption that young man is playing?!?! Many people had probably never seen this "futuristic" instrument before.
Now the Stratocaster is probably the most recognizable guitar in the world. Its' silhouette symbolizes rock and roll. I dare suggest that Leo Fender's creation might be one of the most important inventions of the 20th century.