People are missing what the 3d support here is and why it's there..
For sometime Microsoft has wanted a more fluid interface that allows for more graphically rich and animated formats.
I have been working with the public Avalon/Indigo CTP (preview), and this is what I see the goals...
1) Get away from winforms (aka windows forms, buttons, etc) to a system not requiring winforms.
2) Add a system that allows the user interface to be more dynamic and more accessable by artists and designers (windows programs with the UI designed by artists not programmers). Make the UI as easy to design as an HTML page.
3) Something that's extendable, allowing 2D and 3D elements, that doesn't require programming code (even for button events) just markup.
4) Offer a rich desktop experience with total control of type, graphics, etc.
5) Offer a system that works,in a web browser, in whatever windows explorer is to be called. Avalon express apps do for the web, what avalon apps do locally on a machine.
The closest thing I could say is that a lot of the functionality reminds me of integrating flash into the OS directly. But there is other functionality too, such as a document viewer (with text selection and tracking), and formats such as jpeg, png, and gif are now supported in the OS (kinda like datatypes).
So I guess the 3d is neat, but I think this represents a significant step away into another realm of applications for windows.
So when people are bemoaning a 3d desktop, and I can recreate the Amiga's boing ball demo in all of 15 lines of markup (in true 3d no less).
I see a bright future, with cool look and improvements all around.. For all the naysayers, I think Microsoft is doing something completely original for once, and if it takes awhile so be it. We will all be better for it in the long run.
Also if the 3D UI works and can be added to regular XP, so much the better..
