At CES today, Microsoft announced full blown windows coming to ARM. This is a very Apple like move for Microsoft, but without the whole "oh we had this running for 5 years before releasing it". Sounds like we are in for driver incompatibilities a million times worse than the Vista transition. Even worse, given that Windows biggest selling point is legacy application compatibility, requiring all third party applications to be recompiled negates the advantages of a legacy compatible version of windows. Finally, the lack of a strong infrastructure for supporting the transition (universal binaries, system library management) point to the transition being a painful one.