Over on the Microsoft Windows Team blog they have been discussing the new design of the Logo for Windows 8 and the history of the Windows logos.
I always find it fascinating how logo's evolve over time (for example IBM) and it is especially interesting when the designers explain what they had in mind. Apparently one of the key observations was from a designer from a top agency who observed “your name is Windows. Why are you a flag?”. You've got to love designers. If something is stylised they say it should be more literal. If something is literal they say it is too obvious. They get paid either way.
I think it is pretty clear that in reality the old Windows logo reflected the rich Aero style interface while the new one reflects the starker more angular Metro interface introduced in Windows Phone 7.
However, given that it appears that Windows 8 is going to have both Metro and Aero, perhaps this might have been more appropriate?