I don't really have a particular sound that I like above all others. I loathed loud, cacophonous sounds, partially due to the fact that I have the odd ability to "taste" and "smell" them; many of the louder ones are unpleasant in that regard. For instance, the sound the letter "n" makes smells like sharp, stringent body odor; I'm not even kidding. The same could be said for quieter sounds, like crumbling paper, but to a lesser extent. Heck, I even hate the sound of my own voice, and I rarely talk in real life. There are even times when I wish I could put the world on mute. With all that said, it's quite obvious that I much prefer peace and quiet. I guess that sort of means my favorite sound are my own thoughts.
Further analysis indicates rain showers, thunderstorms, and light music also produce melodious sounds, neither of which is particularly my favorite, though...