I'll take your word for it on Crosby, but as a general proposition the voices of most 1960s folk-rock icons are shot.  We went to one of the LA shows on the Buffalo Springfield 2011 tour, and it was sad to see that neither Stills nor Young could sing worth a damn (Young always had trouble staying on pitch, and he sure hasn't gotten better at it).

The only two guys I can think of offhand who have taken care of their voices and can still bring it are Richie Furay and Chris Hillman (probably not a coincidence that both are devout Christians who have mostly stayed away from drugs and don't tour much).

Bohern are touring as well. Their London gig is of course sold out. I may go and see if I can blag a ticket on the evening.

I do like Nadja. Got about fifteen ep's/lp's. I'll check that out, thanks.

I'd be interested in your thoughts on Thee Silver Mt. Zion. I stopped buying their albums after "This Is Our Punk Rock...". I was put off by the vocals.
What are they up to now?