As Mr Gruber predicted (see here):
This is surely going to cause a lot of confusion in the market – “Hang on, I bought an ARM Windows 8 tablet but I can’t run Windows software?”. It will be interesting to see how Microsoft handle this.
I really don’t see the point of the combined Windows + Metro devices. Why not just simplify and have Metro devices, and Windows devices? I have no problem carrying around my MacBook Air and my iPad.