Oh in the end?* None of them.* I believe that the GUI Desktop
  metaphor is coming close to the End Cycle.* I forsee the
  replacement as something akin to - an immersive environment not
  tied down to Documents, Files, Folders, phones, movies, TV,
  cameras. I'm inspired by because of its expansive capability;
  blocks as a basic unit of information but one that you can
  manipulate and handle and use in any way you desire.* Its not
  "it" but I think it points to a more natural way of interacting
  with computers. The line will blur and disappear between video,
  typing, voice, pictures, as I think it will be possible to
  receive information in the format you most desire. I think the
  emphasis will be on "views"; what you receive will be
  customizable depending on your skill level so that there are no
  barriers to communication. Someone who is 7 years old will
  equally be able to customize their experience to their needs and
  skill levels and primary mode of communication equally well as a
  42 year old computer programmer, or a 22 year old game designer,
  or a 70 year old grandparent. I imagine an iterative process of
  exploration and discovery within the system; where some
  intelligent programming will adapt the system in a general way
  to your needs, without locking you into its decisions. Working
  with computers will be less about function and more about form;
  the immersive experience will allow you to project your wants
  and needs into the system itself; the system won't have to do
  the thinking for you beyond a general way, but instead you will
  imprint YOURSELF into the system as you use it. Imagine blocks
  that are easily programmable.* Look at the MIT project SCRATCH;
  teaching kids ages 6+ the logic of programming by giving them
  FULL POWER to create amazing games and utilities; they have the
  power to take their ideas and make them into something; its
  "extended Kindergarten" model of logical blocks helps them
  understand the nature of processes, Right now, with current GUI,
  there is a disconnect between the processes we desire and the
  systems we have to use; a greater separation between the
  underlying processes that govern a computer's functions with the
  way we use it. But if you learn to truly understand what it is
  that you want to accomplish; and there are STABLE STANDARDS to
  work with, there's nothing you can't accomplish, from creation
  to communication;* (rather than the ever changing "standards" of
  today; and the layers of confusion added for corporate
  protection; twitter blocking image downloads, youtube making it
  more and more difficult to KEEP what we see; (which kids today
  know how to get past easily enough - and they are the ones that
  are going to program future systems). I know this sounds overly
  vague; but it's hard to describe the picture I have in my mind
  about "What is the future of GUI?"* That wasn't your question,
  but it's what I'm answering. :P But I believe it is immersively
  connecting your desires with a set of very basic but powerful
  tools; 1) Create analogies (forms) 2) Add Connections between
  analogies; 3) Use the channels you've created to flow from your
  mind, through your body's preferred communication mode (vocal,
  typing drawing, tactile, video, etc) - into immersive system, to
  allow one analogy to become another analogy;