When I started using Vista I was pleased to see how Microsoft had integrated the search feature right into the start menu known as Instant Search.
I have always been a huge fan of using Google desktop as my local search engine since it makes me very productive when searching my 7 year email archive. I didn't think twice about jumping ship. However, I quickly noticed that my searches were not as effective as with Google Desktop so I decided to revert.
Indexing taxes CPU and disk I/O so here is a quick tip on how you you can stop the Microsoft Indexing Service from crawling the mail that is locally archived by Microsoft Outlook. The easy way out is to simply go to Start -> Administrator Tools -> Services and stop then disable the Windows Search Service. However, this will take away some of the functionality Instant Search offers such as the ability to rapidly find any application by typing in part of the name. So in order to have the best of both worlds we must tell MS Outlook we do not wish email indexed by the Microsoft Indexing service. This can be done by going to Tools -> Options -> Search Options in Microsoft Outlook 2007.
Uncheck any boxes under the "Index messages in these data files:"
Once you ok these menus you will need to restart Outlook for then new changes to take effect.
This method should help you gain some performance you may have lost when installing Google Desktop on Vista and running Outlook 2007.