Hi. I was playing with some fillters/codecs and could get it right.
I'm using MPC-HC with ffdshow and CoreAVC. What I want is to set the "System Default" renderer to Haali.
If I choose "Haali Renderer" in the output of MPC-HC then ffdshow doesn't start up, only CoreAVC.
When it is set to system default ffdshow and CoreAVC start but then I can see that the quality of the picture (when resizing it) becomes pretty bad compared to Haali.

So I checked with graphstudio and the video renderer is VMR. If i remove it from the studio and put Haali instead it all works correctly with ffdshow and CoreAVC and I get good quality with everything I want.
I also tried changing the merit of Haali video renderer to the maximum. didn't help.

That's how it is now: http://img37.imageshack.us/img37/8402/craphe.png
How I want it to be: http://img52.imageshack.us/img52/8210/goodk.png

If you need more info I'll be glad to provide everything I can.

Hope you can help.