Can't remember if someone posted this before, but if so I appologize:
http://www.spheresite.com/
Might be worth checking out, especially if you are looking for a better way to organize your multiple windows while working, without having to rely on that taskbar at the bottom.
Instead of a desktop they should call it a globetop.
Unless it's been significantly improved since the last time I saw news about this app (and I don't see anything on that site saying it has been), it sucks. It is NOT a 3D interface to everything you do, it's more of a 3D alt-tab replacement. It just screenshots every app you have open, and gives you a 3D interface to choose what apps to work with. To actually interact with an application, you go back to regular windows mode.
I can't find the old thread that had references to maybe a half-dozen "3D desktop" demos and betas.
This is close enough.
Looks like YouTube has quite a few videos showing these neato things:
http://www.youtube.com/results?search_query=3D+Desktop
And some are pretty weird, like the idea has promise but they are not really demonstrating its benefits very well, e.g. http://www.youtube.com/watch?v=8qlhP_Ovp8A
- - -
update...
Aha, it was these 2 threads:
http://forums.righteouswrath.com/index.php/topic,2296.0.html
and
http://forums.righteouswrath.com/index.php/topic,1689.0.html
neato ... but would get confusing and/or messed up pretty quickly :p (http://www.youtube.com/watch?v=fclFCjXc5Ls)