Penguin

Xine, originally an open source MediaPlayer, has become a media framework that still comes with a player, if you want one.

Players that are built on Xine include:

You might want to read The Xine HOWTO

To play WindowsMedia in MozillaFirefox for Debian (and probably Ubuntu) install gxineplugin package and w32codecs package. See APT for more details on packages.