Oh Mary, come ON!!! Get real - Dolly and Emmylou are great SINGERS, but FOLK-SINGERS they are not!
And IMOH the pillock who said Ponce (oops, sorry I meant Prince or Squiggle or whatever barmy name the conceited, over-sexed little git calls himself nowadays) really is away with the fairies. :-)
The problem with this thread is that there's a lot of names cropping up that us Limeys have never heard of. But I'd have to go with Odetta and Stan The Man (if Canadians can be classed as American).
It's all personal taste really, isn't it?