It is useless to people who don't have an internet connection. It took me a half hour to figure out how to find a file on my hard drive! If I delete Sherlock will I still be able to search my hard drive?
sherlock is no longer used for Searching the hard drive... it's for on-line services such Ebay, Flight tickets etc (and may I add, only USA at present which is damn irratating)!
If you need to search in Jaguar, there is a new and improved utility over Sherlock, and that is just a finder search. On the desktop (in the finder) go to File-->Find. Or, alternatively, and I don't know why Apple have hidden this as a preset:
Open up a finder window in the desktop --> click View-->Customise toolbar --> You will see a Search box, drag that to the top of your window, and it will permanantly be there when ever you open a window, allowing for quick searches.
Alternatively, ignore what I've said and do what evryone else does as DavidBrit says.