You're linking to Wikipedia to back up your points?
Priceless.
Fact is the OP talks about power usage and 1080p playback.
No mention of games and yet you deem it fit to talk about throwing in a 5 series GFX card? Increasing noise and power consumption.
That may well be the right option for you,But just answer the OP's question FFS...Its not hard.
soo you asked the OP if he had a receiver to take the HD audio you were banging on about or JUST assumed?
So if he is on a budget and does not have a receiver to take the hd audio you lose I am afraid.
Now power consumption, I personally like to have components that do not use much power that does not automatically mean I will not add addional components. E.g. if a 2tb hd cost 1.5 times more than 2 x 1tb I would would still pick the 2 x tb even though it will use more power I would rather have instant the savings!
Point being you can not just assume that the OP will 100% not want the gpu option (which also happen to be quite power efficient anyhow)!