While Longhorn will be breaking some new grounds in GUI when it is released (eyeroll), I am afraid the Longhorn GUI team is too focused on the 'look' and not enough on the 'feel'.  Onscreen objects should not only look great, but also feel right.  If an object looks heavy, it should feel heavy when I am pressing on it or moving it around.  If the surface of an object looks rubbery or plastic-like, objects behave accordingly when objects are dropped on it.  GUI designers have forgotten about physics, something game programmers have not.

Unfortunately, there aren't any physics engines for GUI available today and it would take more than a patch to retrofit existing game physics engine for GUI.  I hope someone writes one so onscreen objects can exhibit real world properties like momentum, collision effects, elasity, etc.  There is also the sound to consider but, until affordable sound projection technologies becomes readily available, noise will be too much to bear in typical office environments.