VLC (Video Lan Client) is CrunchBang's default media player, accessible in the the menu under 'Media Player', it also has the keybinding W-m (Windows/Superkey-m) assigned to it. Out of the box VLC has support for DVDs, MP3s, Flash and many other formats, it also has the ability to stream music and video over a network.
Under 'Media' on the top level menu select 'open file'
or from the terminal:
vlc ~/path/to/file
a list of commands is available in the VLC Help menu or in the terminal using the command:
vlc -H | less