VLC media player is the best free media player available on the net, it can play almost any video file. While it is a great player, some may not like the interface, for those of you who want a pretty VLC player Kantaris is here.
Kantaris is a new media player based on VLC code and Bass audio library. Kantaris has rich user interface something like windows media player. It is integrated with Apple Movie Trailers and Last.fm radio
Kantaris is free and open source project, currently only available to windows.