Zotac's ZBOX AD06 plus puts some graphical zip into a tiny package using an AMD E2-1800 1.7GHz and 2GB MHz DDR3-1333 with 320GB of local storage on a 5400RPM HDD.  They've included a VESA mount so it is quite possible to attach this device to the back of a display and control most functions with the included remote control.  Heat should not be an issue, when displaying 1080P clips it only pulls 16.8W, 27.7W when under full loads such as transcoding.  The benchmark results that TechPowerUp saw might not measure up to a full desktop system but they are certainly at the top of the pile when it comes to similar systems.  You can expect to pay just under $300 for the full system when it becomes available, or about $200 without RAM or HDD if you happen to have some handy.

"The Zotac ZBOX AD06 utilizes the newest generation of AMD APUs, while the Plus model comes fully configured with a 320 GB hard drive and pre-installed memory."

Here are some more Systems articles from around the web:

Systems