Paul Thurrott's "The Road to Windows 'Longhorn' Part Two" provides some interesting information the graphics capabilities of Longhorn, and outlines some more information on the new UI capabilities and the underlying code, called the Desktop Composite Engine (DCE). Here's an interesting excerpt from the article:
... Longhorn is going to have some heady requirements, at least compared with today's Windows. The bare minimum Longhorn system will have to be able to display at least 1024 x 768 with 32-bit color, and it must include a hardware accelerated 3D video card with at least 64 MB of RAM. But this is the base requirement: To take advantage of the fun eye candy Microsoft has planned, you'll need advanced video hardware with at least 128 MB of RAM.
I remember when I bought a 4MB video card back in 1995 and how that seemed like way more than anyone should need. It sounds like the hardware churn around displays and video cards is going to be tremendous going into 2005. I know the gamers are already into this type of hardware, but many of the common folk like myself are pretty far out of step I would imagine.