IXQuick
IXQuick is an excellent meta-search engine. It consolidates the top search results from a number of popular search engines and then displays the best overall results.

Google
Google is, of course, a very exhaustive search engine. They also have a number of other available free tools.

Free Dictionary
The Free Dictionary search box can be used to look up words in a dictionary and thesaurus or to look up topics in Wikipedia.

Yahoo
Yahoo is another popular search engine.

Dogpile
Dogpile can be used to look up people, addresses, and phone numbers