Don't forget that Country & Western used to be "Western Swing", which was pretty solidly jazz, but with fiddles and steel guitars. And there is "rap" music that is funny, wise, and even very powerful--

As far as the greatest, everyone has their own taste, and you can't really argue with people's taste. I do think that Bossa Nova is probably the most complex, rhythmically and harmonically, and that is capable of expressing a great range of emotions with great subtlety, but then, not everyone goes for that, either.

I have noticed, and much to my despair, that far from being a "universal language", people can be extremely divided by music. Rap and Country seem to irritate and annoy some people to no end. And it wasn't long ago that rock, and before that rock and roll, were seriously denounced as tools of Satan.

So it will be interesting to see where this goes--