For years, people have been trying to push the computer into the living room (most notably Microsoft), but it's never really caught on. I think the biggest reason is it's just not simple enough. And, no one wants to have some clunky desktop sitting next to their TV. Media centers are a great idea, but never, in my opinion, been very practical.
What makes the Eee keyboard so different is everything is built right into the keyboard...including the wireless HDMI (so no cords going from the monitor to the keyboard)! I currently have a Mac hooked to my TV, and one of the biggest problems I have with it is the mouse; I can't lay in bed and comfortably use the computer, because I need a hard surface for the mouse. This keyboard has a touchscreen mouse built in.
Asus also has a history of making cheaply priced products (albeit with sometimes cheap parts), and if that is true here, then I really see this catching on.
Unfortunately, it's all a prototype right now so it might not ever come to life; my guess, however, is Target and Walmart will have them on their shelves in time for Christmas next year.
As for the biggest disappointment...Windows 7; they promise a great product and then release the Beta with Vista as a system requirement! So they promise the GUI will run faster then Vista on machines that Vista ran too slow on, and then they say, but you'll just have to take our word on that.