For years I have called for video-download services to be provided directly to a TV-connected consumer electronics product such as the Xbox, TiVo or PS3. This Variety article discusses how the Xbox 360's new Internet-based video-on-demand service is having relative success (where others have failed) due to its available HD content and its direct connection to the TV.
The relative success of video downloads on Microsoft's Xbox Live and disappointment of Amazon.com's Unbox point to two factors that differentiate Xbox from Amazon and its many other competitors — consumers who download a movie want a simple way to watch it on their TV, and those with high-def TVs want high-def content.
A primary reason for its success lies also in the fact that DRM is not a relevant consideration for most users when the content is delivered directly to the display unit of choice. iVOD services to PCs have largely failed because most people do not want to watch TV and movies on their computers. And the DRM used by most of those services preclude users from copying the movie onto a DVD for playback where they want to watch them – in the living room.
FYI: Joystiq has a pretty good preview of the system here including a YouTube demo. Note that the demo was done early-on. As I understand it the slow-downloads and other glitches experienced in the early days have been resolved.