I am not sure why do people think that Microsoft has made a new jump in the desktop world by adding a 3D feature to some elements in its new Windows.
Sun has made its own project for 3D desktop few years ago (3D java-based Desktop). The project is still in progress (beta version), but I think it is cool thing.
The only problem for windows users, is that only a demo version is available (Windows does not separate the shell from the OS, as Unix-based operating systems do).
The project name is: Project Looking Glass.