This is the type of innovation that will lead to a new era of television. While it is unfortunate that this new chapter won't include access to all the content we want on-demand (although great inroads are being made), it will instead be defined by eliminating the hassles between the viewer and the content we already have. I think Roku is on the right track with this device.
Update (2012-01-04): Dan Frommer has a slightly different perspective than my own on this announcement. Frankly, there's nothing within his argument to say that this new Roku "box" won't be a success per se. Rather he presents a healthy, but bridled skepticism about Roku's prospects based on their current performance.