I Want To Watch Anime, Step 1

[ferret]

Download and install the Full version:
http://www.free-codecs.com/K_Lite_Codec_Pack_download.htm

K-Lite is the best available codec pack, and should ensure that anything you download will play. The only file format that I currently know that it doesn't support if "flv".

It also comes with a stripped down "high performance" version of Media Player, simply called "Media Player Classic".

[ferret]

I've been asked to list this as well. Its a lighter collection of codecs that should cover most things, but from a glance at it looks like it will miss some of the odder formats.

http://cccp-project.net/