I've just removed Amarok as it was crashing my system (reported elsewhere), and installed Kaffeine and Realplayer. I have also already installed audacity as I have an LP>CD project underway. Now audacity wants to take over, clicking on an mp3 files opens it in audacity. I've been into file associations and tried to move Kaffeine and Mplayer above audacity for mp3, and even deleted audacity altogether, but when I try to apply this new regime it reverts to the old one with audacity at the top - even if I've deleted it. The same thing happens with .wav , but does not seem to happen with .ogg, but that's not much use!
I have earlier used file associations to change them for other things without any problems.