Asus Essentio CS5110 - World's Smallest Desktop Packing A Fully Embedded Discrete Graphic Card
This computer sits at 200x290x80 millimeters in size; it only weighs about 3.4kg. It has HDMI out as well as 7.1 audio outputs, so you should be good to go to just plop this in with the rest of your home theater equipment.
It has an S/PIDF out for the 7.1 audio and the HDMI comes from that "fully embedded discrete graphics card". For cooling there is a 2-in-1 thermal module that insulates heat from the cooling fan.
Using that cooling process the fan is able to work less keeping the sound output from system operation down to about 23.9dB when idling. So, basically its quiet enough, small enough, attractive enough, and presumably powerful enough to fit right into your home theater system, or act as a really quiet desktop PC, I'm just concerned by how disturbingly similar it is to the designs of the PS3.
[via FareEastGizmos]