Need help with x264

Maybe I am posting in wrong section, but really need good advice from someone who knows this.
We have a 50inch plasma panasonic tv. Have a computer with great processor and memory. I know Classic player with FFDshow codec is great to watch x264 content. Anybody knows a link or the way to configure FFDShow codec for best x264 content output?
Thanks!

the computer is directly connected to the plasma tv - as in Home theater pc

so also have graphic card nvidia 8600 with vista ultimate

anybody?