No surprise. This is appropriately Metro-y:
The design logic is all explained on the Windows Team Blog: Redesigning the Windows Logo.
The post includes a brief trip down memory lane. (Spoiler: the Windows logo used to be a window, then it turned into a flag, now it’s a window again!)
Microsoft says its goal was “for the new logo to be humble, yet confident. Welcoming you in with a slight tilt in perspective and when you change your color, the logo changes to reflect you.”
Feels kind of Scandinavian to me.
Ed Bott 
I would say the logo is more Metro UI, a bit like the top part of a Windows Phone 7.
Kinda plain and boring, like the new UI… 😉
it looks good, I like it!
anyway its a logo, its not like i care much about it. it wont change the fact that win8 is an amazing piece of OS. of course i haven’t tried Consumer Preview, but im sure it will be amazing, for mouse and keyboard and touch.
now its again a window, and its a nice and simple logo, i don’t know what people expected, its not like it had to have million gradients and 3d things, but oh well 🙂
now its about waiting for consumer preview to see how it actually looks like.
I’m a big Windows fan, but I have to say, I’m very disappointed with this Logo. Terribly boring and unsophisticated. I hope they change their mind.