Noatun

Noatun is the default media player in KDE, the desktop for linux.

Compatibility

Noatun can play most media files, but does not allow streamed content.

Noatun uses aRts to play music. aRts will keep running and have exclusive use of the sound device, even if you quit noatun. It's quite safe to kill aRts so that vlc can use the sound card:

pkill -x artsd