VLC Media Player - VLC is a free and open source cross-platform multimedia player and framework.
MPlayer - MPlayer is a movie player which runs on many systems (see the documentation).
Windows Media Player - Get information about Windows Media Player and other Windows Media technologies.
Kaffeine - Kaffeine is a media player for the KDE desktop environment.
XULPlayer - XULPlayer is an open-source media player and converter built on Mozilla XUL and MPlayer.
BSPlayer - The best free media player in the world.