I expect that Metro will continue to be a lousy experience on big monitors, but I expect the Desktop, where PC users will spend most of their time will be an OK environment. I installed the Developer preview on a spare drive and ran it as a production machine for a couple of weeks, and it worked OK, even if it was annoying.

I think Bott's point about Metro being optimized for small screens (the brave new post-PC world) is accurate. I expect MS will continue to support those of us who do real work on PCs; but we may feel more and more like stepchildren, and we almost certainly will be using Desktop.