I'm a WinAMP person, have been for a while. It does transparency, so it goes away and doesn't bother me until I want it. It doesn't try to do annoying things in terms of cataloguing and can be nice and small and unobtrusive (unlike a certain other popular music player). The real killer feature is that it's compatible with my stereo (which connects via USB), so the stereo buttons (and, more importantly, the stereo remote) control WinAMP. There are video plug-ins for it.