I've been running the Developer Preview since September and I think it's great. I've customized the Start Screen as much as I can with a couple third party apps and I think it looks nice. I don't regard the Start Screen as a touch GUI for my desktop, I think it's more like a backstage view of the Desktop.
Personally, I can't wait for a further expansion of metro design. It's everything every software designer would love to see: clean, easy to read, and vibrant.
But, since Windows 8 is about HUGE changes, I wonder if the lock screen a user chooses can become the boot screen background since honestly, most desktop users won't really lock their PCs unlike mobile users. If the lock screen with all the notifications, maybe, along with a boot animation, I think it'd look nice.