Not sure I like it either, but I'm not a big fan of social networking sites, and from the looks of the videos, that's a huge part of the appeal of win7.

So unless its extremely user update-able/customizable, I'd pass for now.
from the sounds of things windows phone 7 will not have much customizations. they are not gonna allow the phone makers to put their own UI {tf3d,touchwiz,etc} on the phones. so right now its looking like its locked down kinda like an iphone. but hopefully the guys at xda can do something about this, we'll just have to wait and see.