There is already a great interest in skinning Vista.
There is still many who will not settle for the default Aero look. I personally was tired of it way before just because of the Aero clones out there.
Here is a screenshot of Windowblinds running on Vista RTM.
http://id.stardock.com/images/vista/...chocolate1.jpg
I think the coming of Vista will actually increase the desktop customization market because there are some very cool things coming.