Surprised that no one has mentioned the Gatlin Brothers, who harmonize with the best of 'um.

And of course, Emmy Lou could harmonize with a chainsaw if she had to. She's done some stuff with Buddy Miller which is real fine but, then again, I like Buddy'd stuff.

Simon and Garfunkle arguably seem to set the bar when it come to pop folk.

The Everly Brothers...

The Byrds...

The Pozo Sego Singers, with Don Williams, hit it purdy good, too.

The Seldome Scene was real tight prior to the death of J. Duffy...

The Righteous Brothers...

Doctor Hook and the Medicine Show. Wow, these guys could sing together... "Carry me, Carri"... Like I said... Wow...

Well, that's my short list.

Bobert