For the past 8 years and may be as far back as the Apple Newton days, many including myself had speculated about Apple releasing a tablet computing/media device.
This device will not be a replacement of your notebook computer but to supplement the PC you already own.
Ever since the introduction of the iPhone and the mobile version of OS X, I had imagined Apple releasing something that sits as a conduet among the Apple TV, iPhone and the Macintosh PC.
This device will act as a remote interface to the Apple TV, able to bring up detials about the show or movie (ie. the type of content available from IMDB.com) you are watching. Able to receive and make calls via the iPhone, or conduct video conference. Able to leveravge the computing power of the Mac if one is available, to perform any computing that is too resource intensive for the Apple Media Tablet. You can imagine it being the view into the personal cloud created by the connected devices on the network.