Avalon, Sparkle, UI Design
This quote on Slashdot sums up my thoughts on this:
That's right folks, no more of that annoying consistency between GUI applications, now anything that the guy down in marketing can draw is a workable GUI - just think of the possibilities. Microsoft is not a believer in consistent elegant or intuitive GUIs, Micorosoft is all about empowering developers, and graphic designers, and wackjobs with no aesthetic sense. You too can finally design and implement that stunning piece of GUI genius you always imagined.
Microsoft has clearly switched from a world where GUI consistency was encouraged, to a world where "emotional connection" and creativity and branding are encouraged.
This is good if your graphic designers are good application designers, but in all but the best companies, they're not.
In the past, we could point to some guidelines, list all the reasons we should stick to the guidelines, and override the guy who wanted to have the menus at the bottom of the window instead of the top (for no reason other than that it'd be cool and different).
Now? That sort of cool and different is encouraged. It's a great day for graphic designers, and a great day for users of software developed by the very small number of companies with great graphic designers, but maybe a bad day for everyone else.