I found this news article today which tells that Google has raised objections on Vista's new features. According to the article:
1. It is difficult for users to disable Vista's integrated indexing and search
2. If a second desktop search application was installed, the computer would slow down as two competing indexers churned through the hard drive
3. Microsoft's search was the only tool allowed to generate results in Vista's search bars, which appear in several places, including the Start menu, in the Windows Explorer file manager and in the Control Panels main display
If Microsoft believes that its desktop search is so good that users will not switch to other desktop searches, then it should not be doing this. It should just allow users to choose whatever they want. Anyways, I have not used Vista till now and i don't know how the product looks like. Probably i should take a peek.