VLC (VideoLAN Client) is one of the most popular video players on Linux, together with players like SMPlayer or Kaffeine. It plays many audio and video formats (including Xvid, DivX, H.264, Theora, WMV, Real Video, Ogg, MP3, FLAC, APE, AC3, WAV) together with DVDs and DVD ISO images.

The version which comes included in the Debian Lenny repositories is 0.8.6h, which uses the wxWidgets kit and it is kind of outdated now. The latest release of VLC is 0.9.8a, which is now built in Qt 4 and includes several improvements over the 0.8.x series.