After spending a few hours at the weekend trying to get my new Mac Mini media center to play all my videos though Front Row, I found this today. Perian is a free plugin for Quicktime which allows it to play everything that VLC will play. Rather than searching for all those Quicktime plugins and codecs and then having to install them you can now just use this.
So if you are now having to use Quicktime (on front row), don't bother searching for all the codecs just download Perian.