VLC Media Player - VLC is a free and open source cross-platform multimedia player and framework.
MediaInfo - MediaInfo is a convenient unified display of the most relevant technical and tag data for video and audio files
foobar2000 - An advanced freeware audio player for the Windows platform.
VideoSpec - VideoSpec is a free AppleScript studio App (Xcode 3.
Winamp - Winamp is a media player that allows users to play multiple-file formats, arrange media in a varied file-management system, and play unique media with AAC encoding.
MediaInfoXP - GUI for MediaInfo, an open source tool for displaying technical information about media files.