Most Influential American Musician of All Time?

How about Ray Charles; he had best sellers on several different genres of music.

I don't think there's a way in hell to answer this, but here's a my list of nominees:

Jazz:
Louis Armstrong
Duke Ellington
Charlie Parker
Miles Davis
John Coltrane

Rock:
Elvis
Jimi Hendrix
Bob Dylan
Chuck Berry
Jerry Lee Lewis
Little Richard

Blues:
T-Bone Walker
Muddy Waters
Robert Johnson
BB King

Country:
Hank Williams
Patsy Cline
Merle Haggard
Jonny Cash

Classical:
Aaron Copland

Miles, Jaco, Hendrix.

Probably Miles Davis and Elvis Presley.
And many others.

Without a genre of music, it's a dumb question.