mmm, you are looking for a Low Idle power build, that dont exist in amd unless you are going with the a4 fm1 cpu, now, What are you looking this pc to do?, i see this as a Desktop pc not an Htpc. This build will alow you to run games, watch movies, web surfing and office withtout a hicup, but as i said, its not an htpc.
Htpc are supposed to be small, Low power (160w max) and used to stream videos, light gaming and downloading or watching 1080p movies.
Overall its a good build but you could do way better if you went with intel.
and the gpu you already have, you should be able to run Hd videos, play with better fps in your games and go down a notch in the Ram memory, getting a Cheap Ram like this because you wont be depeding on the Ram anymore.
Also remember than The Intel build has a better path for upgrade, with the Amd a8
apu, you can only go with a 6670 to enable crossfire and with the g850 you can get any video card you want, and get better performance in the future.