Yahoo! Desktop Search: Highly Recommended
Two parts to this recommendation:
First, if you are still just using Outlook find or that horrible windows search function, get one of the free new desktop search programs NOW! I have tried several, and in general they have been the most useful utility I have tried in years. These programs index your email, hard disk files, and web history together for unified searches. There is some overhead in the initial indexing (run it overnight) but from then on these utilities provide lightning search results to your whole hard drive.
Second, once you are ready to try one, get the Yahoo version. Like Google's and others, it is free. I have tried several of the others, including Google's, but the Yahoo version is faster, easier to use, and presents the results in a more useful format. Also, I had conflicts between the Google version and Zone Alarm, and the Yahoo program got the editors choice award at PC Magazine. You can download it free here.