It's probably not the kind of answer you were soliciting, but one of my favorite voices in the world is that of my eldest brother. His voice is soft, engaging, and mellifluous. His use of language is poetic, and to listen to him relate even the most mundane tale is a joy. Obviously, the family connection influences my preference for his voice greatly. I have always felt that as long as he is around, everything is going to be OK. He always looked out for us all. He suffered a small stroke a few years ago, and his mastery of language has suffered a little since then, unfortunately.
If given the choice of listening to any voice in the world, it would be that of my eldest brother, before his stroke. I wouldn't care if he was reciting Yates, a grocery list, or telling a story about one of his friends or neighbors - his story-telling abilities were so good, and there was a very caring and engaging person behind them.
PS - I still love listening to him, of course.