VLC Media Player
The VLC Media Player is a free open source cross-platform media player developed by VideoLAN and first released on 2001-02-01. The player supports dozens of video and audio formats, playlists, streaming audio and video protocols, and many optical disc formats and their menus. It can even play large portions of corrupt files or partial downloads. It also has a vast array of features and customizations. It has been my favorite video player for the past decade, so much that I don't even bother with other video players.