This is doing the rounds on design blog at the moment and quite rightly so! I think it's a vast improvement on the current Window's UI but keeps to a traditional 'window-based' desktop experience.
The latest official designs coming from Microsoft for Windows 8 has radically changed to a 'titled' experience design to fit in with their mobile UI, something that I don't quite agree with since they are very different interactive experiences. Here is a Windows 8 video released last year by Microsoft:
I very much prefer Sputnik8's direction with his Windows concept, there is more information about his designs over on The Verge's forum and there is plenty of interesting feedback from the community too. I have tagged this under my surveyor brief because portions of the aesthetic and use of whitespace is something I'd like to implement in my website design for the client.
