It doesn't make sense of having a touch interface for a desktop if I have to extend my arm, then my hand then my finger to touch and manipulate things on screen when a miniscule mouse movement will achieve the same thing faster with more precision and accuracy.
I see touch being for content-consumption devices (iPads and smart-phones) and mouse for content creation. MS would do well to simply ask the user which interface they want for Metro at installation time. A simple question-hell if they want they can even guess your hardware and default to touch or desktop environment-, but forcing desktop users onto a touch environment is a disaster waiting to happen.
On topic: i like the drop down menu that can be created with Magic Menu, I like that I can drag and drop a drawer into a file requester and lists the contents, I like the idea of screens but most of all I like that the active window can stay behind instead of being always to front
