Tired of Windows Search thrashing your hard drive in XP or Vista? Upgrade to Windows Search 4.0, the final version, today. You can download it for XP, Vista and 2008 here.
Previously, a preview release was available. If you are running Vista, this is basically an updated version of the engine with many optimizations and has remote indexes enabled.
If you use Search, which pretty much anyone running Vista or Office 2007 is, I highly recommend installing this update.
Case in point: In the past I would disable Windows Search on my laptop because it had a habit of running all the time and slowing down the system in general. Ever since the 4.0 Preview release, I leave it enabled and set the indexer to 'run immediately' through the group policy so that whatever it needs to index, it will index my hard drive contents and Outlook e-mail right away.
I would rather have a brief period of high hard drive I/O than a long drawn out session of throttled I/O, which could potentially keep me awake at night if my system was constantly indexing overnight, due to the system being idle.
I know that might sound fickle, but it has happened in the past.
If you want to read more about the technical aspects of the upgrade, go here and here.
The product team behind this release are a cool bunch of folks that I have been in contact with for the past few months and they have been really eager to make this is great release.