Lots of interesting new features in the core of windows (fast boot, process management, low memory footprint, low power mode, ARM support, etc).
I think the metro stuff will be about as popular as WPF has been. Web apps appear to be the future of development, except in special cases where heavy resource usage is required (3D modeling, games, etc) and I don’t think you’ll see a metro version of those.
I do think the WinRT is a good think and although they made it seem like it is connected to the metro stuff it seemed more like a framework akin to the .NET framework to me. If so where does that leave the .NET framework?