Have just found this thread, and what a sensible and reasoned discussion.

My own view is that in an ideal world/gig there's a place for all - unaccompanied and accompanied song, and purely instrumental music, and indeed monologues and stories. I love all of these, in balance.

The song being performed to some extent dictates the mode of performance. Some songs just don't work unaccompanied, and vice versa is also true. As several of you say, communication of the song /story/emotion is of paramount importance. Yes Mr Padgett, it is after all the traditional way. And some songs need the freedom of phrasing that accompaniment denies them, in order to best communicate that. Some songs are written to communicate best when accompanied however, I won't deny that either - but it's not easy to explain why the complex mix of emotions works better in the service of the song with accompanied chords or harmonies. Whatever, in any performance, accompanied or unaccompanied, surely nothing (whether fussy chords or fake accent) ought to be to the detriment of actually communicating the song.

Sure, as an atrocious guitarist (and fiddle player) myself, I salute any capable instrumentalist. I admire and respect those who can do well what they do, whatever that happens to be. I realise however that "well" is for many not a mark of quality but a personal value judgement that is born of often unreasoned or uninformed prejudice. Which is why most clubs won't even consider booking an unaccompanied singer, even for half of a double bill (probably the best "compromise" if compromise is needed). Sure, there are some who I couldn't "listen to all night". But the truth is that there are also unaccompanied singers who can/would/do carry a night, or extended set, simply due to their breadth or range of material (or variety in delivery/pace).

I too have been bored rigid by a self-absorbed accompanied singer (a professional) yet enchanted by an unaccompanied singer (an amateur) who had a decently wide range of songs and included chorus songs which generated at least some of the necessary variety in texture. Oh yes, and who engaged their audience by communicating interest in the actual songs rather than a dull succession of personal anecdotes to cover interminable tuning of instrument.

But I've also been bored rigid by just one half-hour guest spot by an unaccompanied singer whose repertoire consisted entirely of intentionally comic songs all done in the same manner. Even though I like comic songs!
Jerry's comment >>A full concert of unaccompanied music works as much as anything on the personality of the singer ... and a good mix of humorous, upbeat, ballads and songs with choruses<< rings true here in the UK as in the States.

If I booked acts for a club I'd never just "write off" an unaccompanied performer simply because they don't play an instrument. And I'd not automatically consider a performer more favourably simply because they can accompany themself on one or more instruments.   

There's my two pennorth at any rate.