I regard the guitar accompaniment (i.e. my own) as integral to the performance of the song - the voice and guitar working together. At least, that's what I try to do. And I think I'm a better guitarist than I am a singer - mind you, I would only ever describe myself as a 'competent' guitarist!

Is there a trend developing in this thread, though? I get the impression, from their comments, that several of those who sing unaccompanied do so because they feel they can't play well enough. I'm not going along with the 'jealousy' argument - seems more like 'modesty' to me.