Instead of WHO, I think WHAT: pedal steel, fiddle, mandolin, dobro, harmonica, 12 string, banjo, and honkytonk piano. All bring out the best in country.
The ladies: Loretta, Dolly, Tammy, Kitty, Patti Page, Tanya Tucker, Pam Tillis, Patty Loveless, Lee Ann Womack, Sara Evans.
The gents: George Jones & Strait, Merle, Johnny Cash, both Hanks, Mark Chesnutt, Joe Diffie, Randy Travis, Joe Nichols.
Many others not mentioned are not meant to be excluded... the list is endless.