I'm just thinking that the idea behind Windows 8/RT is flexible enough that it can be configured to work in different ways.
Here's a couple examples:
Car infotainment system: It would be very simple to put a touch screen into a dash, and include GPS and a 3G modem. Ideally the interface should be configured so that accounts are tied to the keys, with an easy way to keep information secure from people you don't want to have access to it.
Set top box: Take Windows RT, add a DVD/Bluray drive and a Metro playback app, and you're pretty much done. This would also need to have a means of having basic functionality without logging in (disk playback, weather app, internet, user selected apps), but you can quickly log in to access all functionality. Ideally it will automatically log you out when idle for a while or while playing a movie. This could use either a Kinect interface or (possibly more precise) something like a Nintendo Wiiremote interface.