My feeling is that some company is gonna do that eventually, use the set top box as the home hub, but there are some convenience issues to be figured out.
And add a feature to listen to commands like "Show me X on my phone" or "Send this to my phone" and it will display whatever you just asked for on your iPhone. Or even "Send this to [contact name]".
What I haven't seen is something like the electronic-paper Kindle... a calm display. Most of the time I have my laptop and tv on quick shut-down because the ambient light feels grating (maybe it's the feeling of losing energy? not sure why it annoys me). A calendar or XKCD board would be awesome.... have the echo just populate a poster with stuff that's slightly irritating to lookup... this leads into an idea of having 'settings' for the environment/ room...hmm