Personally I think the best use for a device like this is not as a media or small business server. The cloud is rapidly taking over all those functions and is easier to manage.

What a device like this could really revolutionize is the communication between what are now "dumb" devices. I could imagine this thing using NFC or Bluetooth to talk to your power meter, alarm clock, even your fridge. Instead of a whole wifi stack in each device just put cheap NFC chips in them and allow a small server to talk to the rest of the world. With the right third party ecosystem I could imagine one of these in every house.