VLC is a open-source multimedia framework, player and server.
The media player that fulfills all your needs. It handles DVDs, (S)VCDs, Audio CDs, web streams, TV cards and much more.
With VLC, there is no need to continually update many different codec packs. VLC comes with nearly every codec built in!
And whats more, VLC can play back your files, even if the media is damaged! Missing or broken pieces wont stop VLC. All the video and audio information that remains can be played.
It can be download here: http://www.videolan.org/vlc/
or install using Synaptic Package Manager.