Used to be simply the music/beat when I was younger. Now I find myself gravitating more and more to the singer-songwriters, I seem to get the best of both worlds. James Taylor, Billy Joel, Jackson Brown, etc. The older I get, the less the I listen to the newer stuff.
One of the things I enjoy about smooth jazz is that much of it is just instrumental. I can enjoy the music, and I can create whatever lyrics I want in my mind. Going to a Smooth Jazz festival in Cabo in November, my wife and I will be celebrating our 30th wedding anniversary while we're there. Looking forward to it.