List of Codecs/Plugins to install? +a few general questions

I just did a clean format of my hard disk, and having heard so many good things about BSPlayer I deceided to give it a try. Do I need any plugins/codecs? If yes, could anyone give me a link?

Also, what can I do to prevent Windows Media Player from playing my video files? I told BSPlayer to assosiate all video files with itself when I installed it, but WindowsMediaPlayer keeps opening them, and I can't seem to be able to uninstall it (I went to add-remove programs/windows components and unchecked WindowsMediaPlayer... It seemed to uninstall successfully (the box is unchecked now) but it still keeps opening my movie files..)
Thanx