I don't know if this has been linked before but:
Watching h.264 videos using DirectX Video Acceleration (DXVA). | My collection of short anime reviews
I highly recommend people use those settings over just installing CCCP/VLC ect. It's really simple and works a hell of a lot better than just running it off software settings if you have a video card that supports it.
Having Advent Children Complete in 1080p only taking up 8-13% CPU is pretty awesome.
Note to Nvidia users: I tested both the first page DXVA method and the alternate link CUDA/CoreAVC method. The first page's setup is far easier, has less problems, and performs better from what I saw. It also doesn't require you to either pirate or pay for CoreAVC.