XMMS is an open source media player similar to WinAMP. It supports most common audio formats, and also plays some videos.
XMMS has good audio compatibility, and can play a range of video formats. XMMS does have some problems when receiving streamed content.
% vlc --sout http/ogg:127.0.0.1:8080/my_audio.ogg
As a temporary hack you could append "?.ogg" to the MRL you give XMMS.