Ingo Hinterding pointed to the SphereXP project and Sun’s Project Looking Glass. Sphere looks quite easy to use – but doesn’t seem to be an incredible enhancement. Sure: you could have open 130 windows and see them all almost at once — if you rotate fast enough! All the 3D approaches I have seen have one major drawback (that Expose has not by the way): the viewpoint. It means that most of the space is outside the view. So there is the same problem as with virtual desktop tools: you need to remember where you have left what.
I do believe, that one day the 3D graphics hardware in almost every consumer PC today will be responsible for the next generation desktop interface. But I believe it won’t happen as long there is no departure from the 30 year old interface paradigm.
I have ideas about that. But I won’t tell anyone unless he/she pays me for it ;-).