I think this site http://www.real.com/player/8/index.html still gets the free RealPlayer 8 Basic - which is the less intrusive version.

I've installed Jet Audio, as recommended by Clinton - looks flashy enough, with bells and whistles, but it doesn't seem as easy to work with for streaming files than Real Audio. I suspect it can do everything, but it nees a bit of study, and that's not too good if you're trying to get someone to download a program in order to hear a sound file.