VLC Media Player
(Version 0.8.6a)

VLC Media Player is a free cross-platform media player, supporting a large number of multimedia formats (avi, mpg, mov, wmv, DVD, VCD, etc.), without the need for additional codecs.

It can also be used as a streaming server, with extended features (video on demand, on the fly transcoding, ...)

VLC media player has a simple interface, a light memory footprint, fast loading time, and also supports skins. You can use it to watch DVDs or other video files.