The version of the board with a 1GHz CPU needs only passive cooling, while the 1.5GHz model requires a small cooling fan. VIA claims "average operating power consumption" for the board of just 13.6W.
We don't having pricing info yet, but the EPIA EX's media-oriented predecessor, the EPIA SP 13000, is currently selling for between $226 and $255 at online vendors. I suspect the new board will fall into a similar range, with perhaps a slight premium. VIA plans to show off the EPIA EX at the Consumer Electronics Show next month.
Of course, any system based on the C7 processor will have to live with its performance limitations as well as its convenient power/thermal envelope. If you want to build a more powerful media PC, check out the Couch Potato spec in our latest system guide. The Potato may be larger and draw more than 14W, but it should be quiet and extremely responsive, as well.