My source(s) indicate that WMA/WMAPro will not always be converted to multichannel PCM before going out over HDMI. Additionally, because Windows Media DRM allows for differing output protection levels different movies may result in different behavior.

But that's a good point that you'll need to receive the audio over HDMI+HDCP anyway, if the audio must remain protected, which means you need an HDMI pre-processor.

I think HD content may actually make me stop watching domestic stuff all together; I've already stopped watching television. I'll just buy imports only.