Glenn posted the before/after pictures of the Prism Reference Implementation application.
I was very impressed when I saw how they got from the traditional developer styled UI:
To this UI:
Something else that Glenn said couldn't be stressed enough, this metamorphosis has happened in two weeks by a single developer.
I have worked on skinnable (win forms) applications, and that kind of thing just doesn't take just two man weeks, if it is possible at all.
This make the WPF story much more compelling.