Plays music and video
Showing software for all platforms
The MPlayer media player can play a wide variety of media formats. It can also save streamed content to a file. A companion program, MEncoder, can take an input stream or file and transcode it into several different output formats, optionally applying various transforms along the way.
XBMC is a media center application for Windows, Mac OS X, Linux, and XBox. It's easy to use, looks slick, and has a large, helpful community.
Media Player Classic (MPC) is a compact media player for Microsoft Windows. The application mimics the look and feel of the old, light-weight Windows Media Player 6.4 but integrates most options and features found in modern media players. (From Wikipedia)
Elisa is a cross-platform media center that connects the Internet to an all-in-one media player. It features an intuitive interface with a professional look and feel that can be used with a standard TV remote control.
Songbird is a dual-platform (Windows and Mac) media player based on Mozilla code. It lets you play, manage, and discover music. You can customize its appearance with skins, and create dynamic playlists that automatically update based on criteria you set. Supports some media players and can support iPods with an extension.
MediaPortal turns your PC and TV into a home theatre. The software allows you to listen to music files and Internet radio; watch and store videos and DVD;, view, schedule, and record live TV as a digital video recorder; and more. Lots of plugins that offer additional features are available from the community.
Kantaris Media Player aims to be an all-in-one audio and video player. Its GUI and features are similar to those of Windows Media Player. Video playback is based upon Videolan Client (VLC), which enables Kantaris to play almost anything without the need to install any codecs separately. It features an attractive skin, some nice audio visualizations, and integration with Last.fm and Apple Movie Trailers.