VLC Media Player

Click on image to enlarge

There are several media players available for free, but arguably none are as versatile as VLC Media Player. It can cope with virtually any video format even if the codec is not installed on the host computer, and can even play DVDs and VCDs. Unlike much freeware, VLC Media Player is not only available for the Windows platform but Mac OS X, Linux, Ubuntu, etc. For technofiles, the program can also be used to stream videos.

Available from http://www.videolan.org/