Lots of people missing the boat..
WinRT / Metro was borne out of demand. People are demanding applications that can run on any kind of device and an ecosystem that can fulfill that demand.
MS has been on a "3 screen" bandwagon for 10+ years and it amazes me people still write it off as if its new and misguided.. just where have you been?
Metro is their design language/UI for Phone, TV and Computer - regardless of form factor in any of those "3 screens". The UI is interactive for mouse, touch, gesture, voice, keyboard, remote & controller experiences and lends itself to being super intuitive and simple to use.
Its a paradigm shift for sure, but its a shift in a direciton i'm enthusiastic about because it opens the doors to new possibilities and yet somehow they were able to maintain great backwards support capabilities.
Not only that, but windows 8 as an OS has been improved vastly, fast boot, low memory foot print, more secure, hypervisor support, better deployment options.. the list goes on and on.
oh well.. /rant lol