Questions of the Ages: Who Are the Most Influential American Musicians?

The other day I was in a conversation that asked the following question:

If you had to represent American music to the rest of the world, which 3 artists would you select? I have also had similar conversations that asked which 10 artists. Here's my answer to both:

1. Elvis Presley
2. Stephen Foster
3. Duke Ellington

The other 7 (not in any particular order)
4. Miles Davis
5. George and Ira Gershwin
6. Hank Williams
7. Bob Dylan
8. Skip James
9. Bill Monroe
10. Woody Guthrie

There are lots of people who are really close. I really wanted to include a newer artist but I wasn't sure who. I thought about The Ramones but I'm not sure that they were that much more influential to American music than The Clash so it didn't seem right. I thought about Nirvana as well. No doubt they were huge but they were also so in debt to bands like The Ramones and The Clash that I just wasn't sure. Of course Dylan was heavily influenced by every other person on here so I don't know if that matters.

Maybe I've forgotten someone who clearly deserves inclusion on this list but I think I would pick most of these people most of the time.

How would you answer this question?