What Hardware's Needed for Audio Pass Through via HDMI?

Hi - am new to the forums and am, myself, just a casual Plex user on a Hackintosh who is ready to build an HTPC for the living room (living room has a 7.1 surround sound setup with receiver and HD television). My media is self-ripped Blu-Rays in MKV format (handbrake, h264) with DTS and AC3 audio passthrough.

I want to go from my *new* HTPC -> HDMI -> Receiver -> HDMI -> TV.

My question stems from some struggles I've had with Plex and audio passthrough over HDMI ... what do I need to know to make sure I get the right hardware and software that will allow me to send the audio over HDMI without fooling with it first? Right now, I've been keeping the DTS and AC3 streams but I would rather save the HD audio if I could and still pass it along.

- Can anyone point me in the right direction?
- Am I limited to Windows only? (I havent had a Win machine since 2002 - only Linux and Mac!).

If I had a preference, I would like my HTPC build to be compatible with a Hackintosh setup (in the event that I repurpose it later) - I know this will make it more expensive because I will be limited to Intel. For example, this recent suggested build. Also, if I had my preference, I would rather run Linux but not if its not going to work smoothly (my wife and kids need to use this, not just me).

Thanks for your advice.