ASUS should be fine. But what quality are you looking for?
You mean it's already fitted to a desktop, so why would you want to know if it's good? You've already bought it haven't you?
As a HTPC that motherboard has everything it needs.
If you are using its onboard video, if you bought a BluRay drive, you may want to buy a graphic card with BluRay HD264 acceleration, and a HDMI output, otherwise it'd be likely that it'd lag playing HD content.