I was reading Digg, and noticed an article about a showcase of 3rd-party apps for Windows Vista. I was curious, so I took a peek...lots of clips of programs with Tom Skerrit narrating.
Anyway, if you visit the link above (http://www.seewindowsvista.com/ skip the intro, not much point in it), click on "Turning Information into Action", and then scroll down on the list of clips on the right.
The second-to-last clip is titled "Right Hemisphere - Proprietary format? No problem!"
The clip talks about taking data from proprietary formats (they are specifically talking about CAD, in this example), and making them available to "anyone, anywhere, on any platform".
I couldn't help but think that perhaps Microsoft's OpenXML is about much more than MS Office, and that they may be trying to position it as the new de facto (proprietary...ironic, eh) format for document exchange. If there is new graphics capability in Vista that this new uber-CAD-format makes use of, perhaps all of the posturing about OpenXML being the best has more importance in Microsoft's grand design than they have been letting on.
Internet Explorer gained Microsoft a lot in the market by its inclusion in Windows, and making OpenXML an automatically-supported format in Windows (to whatever extent) *could* do a lot to gain them back market share...if there wasn't a robust, capable, complete, and ISO-approved alternative in the form of OpenDocument Format.