VLC media player is a highly portable multimedia player for various audio and video formats (MPEG-1, MPEG-2, MPEG-4, DivX, mp3, ogg, ...) as well as DVDs, VCDs, and various streaming protocols. It can also be used as a server to stream in unicast or multicast in IPv4 or IPv6 on a high-bandwidth network.
VLC plays absolutely anything. It supports an enormous number of multimedia formats, and does not require you to download additional codecs. VLC features a complete streaming server, with extended features like video on demand, on-the-fly transcoding, granular speed controls, frame-by-frame advancement and more. It can also be used as a server for unicast or multicast streams in IPv4 or IPv6 on a high-bandwidth network.
VLC Media Player now features fully customizable toolbars, customizable Skins, supports playback for broken files as well as zipped files, and so much more.
Download: VLC Media Player 2.0 RC1 | 20.9 MB (Freeware)
Download: VLC Media Player Portable | 18.3 MB
View: VLC Media Player Website | Release Notes
Thanks to Mephistopheles for the tip in Back Page News.