Copernic: Software to search, find, and manage information
If you're in the information business (or you just do a lot of searches) and you can only have two tools...these are they.
Google Toolbar is a powerful tool that puts itself right into your browser. For fast, flexible, searches of what is probably the best search engine (Google) out there, this is invaluable. It also includes features like an extremely fast way to search for your terms on the page, the ability to search a single site for a term, highlight your terms and even search Google Groups quickly and easily.
If Google doesn't find it, try Copernic Personal Agent. A powerful piece of metasearching software it searches across a broad spectrum of resources to find your information and collect it all for you in a useful format. You can download a free version, give that a try, but I upgraded to the Personal Agent for a small fee.