Sorry if any of this is repeated from earlier in the thread!!
Use Shark007's codecs:
http://shark007.net/
with MPC-HC:
http://mpc-hc.sourceforge.net/
And everyone should check this site out, it's AWESOME:
http://ninite.com/
It does a single packaged installer w/o the nagware and toolbars etc for LOTS of common stuff, so cool! Just check what you want and go.