One thing that deserves being pointed out, repeatedly, about Windows Phone 7 is how the UI is pretty much unlike anything out on the market today. Whether it's iOS (who lifted their layout from Palm's Garnet), Android (same) or even WebOS (more unique than the first wo), the Windows Phone 7 "style" is certainly eye catching.
So much, in fact, that Microsoft has filed an application for a trademark on it--guess they're fearing the rise of the clones, at some point, eh? Of course just because you file doesn't mean it will be granted, but it's probably always smart to get these things in writing, in case lawsuits start flying again later on. Also, lets just say they're very specific on the filing:
The literal element of the mark consists of PHONE PEOPLE MESSAGING OUTLOOK. The mark consists of eight boxes; the upper left-hand box containing the word "PHONE" along with a telephone receiver; the upper right-hand box containing the word "PEOPLE"; the lower left-hand box containing the word "MESSAGING" along with a character face; the lower right-hand box containing the word "OUTLOOK" along with the letter "O", an envelope and a check mark; the lower four boxes are empty.