Vista Codec Pack is a set of filters and codecs that will allow you to view your favourite video and audio files. It is a freeware video codec application that's comprehensive, advanced and powerful.
Here are some screenshots to illustrate the features and user interface of this application:
Shark007 Codecs
x264 Video Codec
DivX Codec
K-Lite Codec Pack Standard
K-Lite Codec Tweak Tool