VLC - Windows / Mac
VLC Plays any file of any kind. It does 5.1 and 7.1 surround and can handle audio formats from any country. It doesn't have the best library, but that part is improving.
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Winamp - Windows
Winamp is the best windows based media player. It has tons of options for playback, lots of plug ins made by users, and a highly configurable library.
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Media Monkey - Windows
Media Monkey is another great way to free yourself from Windows Media Player. It automatically finds and inserts information for songs. It also offers fast searching for movies and music within your library.
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Real Player - Windows / Mac
Real Player can be a bit tricky with advertising but it's a solid player and some government sites still use it as their preferred internet streaming provider.
Click Here To Download Real Player