I think anyone who posts to this thread realizes that such a 'list' is entirely subjective. I too have seen singers mentioned thatI don't like at all, those whom I appreciate very much but who don't really have a good 'voice' in my opinion and those who definitely have beautiful voices. I agree with the comment that there may be even more beautiful voices out there that haven't been recorded and are only being heard in limited circles - small clubs and coffeehouses. But there's no harm in a thread like this as long as we don't start to fight amonst ourselves about "What is Folk".

Of course it isn't all about the quality of the voice - there are folk singers that don't have good voices but they can deliver a song skillfully and effectively - that's more important than a good voice. It doesn't hurt to have both the voice AND the delivery though!

Someone mentioned Liam Clancy. I agree, and would add the late Tommy Makem. And, it's still folk, I think - the Fado singer Amalia Rodrigues. For voice quality and delivery it's hard to beat her.