Why is Google complaining about Vista desktop search? Answer: because it's better. There's no other valid legal reason, since Microsoft had shown prototypes of desktop search (in the form of WinFS) long before Google ever released their own version.
I'd be sad if it went away because Vista search the only usable desktop search I've tried, and I've tried all of them. Hit the Windows key and type. And the indexing generally doesn't harass me, hang my system, or crash. (Google's windows tools crash on me all the time... Google Talk especially). Plus it actually does a better job of ordering results. Finally, I've always been concerned about privacy with Google Desktop.
I think it would be really sad if Google's legal efforts here reduced consumer choice -- MY choice for what I want in desktop search. I want integrated search in my OS, be it Linux, MacOS X or Windows. Microsoft's an easy target because of their DOJ agreement. I'd really hate it if Google is just playing on that for competitive purposes, rather than having any real interest in the consumer's desktop search desires.