VLC is one of the most popular open source programs in the world.  Over 100 million copies have been downloaded since the 1.0 release, with an all time download count of nearly 400 million.<p>They support not only H.264--which has a relatively reasonable, low-cost licensing system--but many formats whose licensing models are absurdly overpriced and unreasonable (e.g. MP3).  And furthermore, VLC not only supports open standards like H.264, but also plenty of proprietary formats, like VP6, MSMPEG4, and Real Video.<p>They don't pay a cent to anyone.