Codecs
K-Lite Codec Pack
One of the best collection of codecs which enables playing all sort of movies
K-Lite Mega Codec Pack
K-Lite Mega. Complete and famous package of audio and video codecs. (Includes media player)
DivX Plus
A powerful player and converter packed with a bunch of basic tools for streaming and converting videos.
Windows Essentials Codec Pack
A compilation of codecs which one must have to open files downloaded from the Internet.