Poser on Linux would be good.

I suspect that both Microsoft and Apple will need to retain some form of power-user desktop interface. Both bank heavily on their developer userbases, as well as computer graphics users.

Whilst the interfaces for these user groups could well evolve into something way better than the basic keyboard / mouse centric desktop UIs we have now, the requirements are very different from the masses, who, indeed, don't really need desktops at all.

For standard / mainstream application users,  an interactive (gesture, voice, touch sensitive) projection (from some sort of portable device)  that followed them around their environment is likely to be the kind of way it goes... I think.

Developers and designers, for some considerable time to come, will still need a more traditional workstation set up, I reckon.