Web Directories - Results are hand-picked by "experts"
Yahoo Directory - The Yahoo! Directory is a human-created and maintained library of web sites organized into categories and subcategories
Open Directory - The subject directory used by Netscape, Alta Vista, Hotbot, Lycos, and others.
About.com - Hundreds of specialty areas, each updated by a professional guide.
Pandia.com - Nice, clean interface, full of tutorials to help you get the perfect set of results.
Search Engines - Results are chosen by a program
Google - Google ranks searches based on number of times your keyword has been cited by other web sites.
Yahoo Search - Yahoo Search returns a web pages that contain the keyword you typed. These results are a combination of relevant web pages and web sites provided by Yahoo! Search and the Yahoo! Directory

Ask.com - Type in questions as you would normally ask them. Has a nice binocular feature to preview a thumbnail of the site prior to choosing it
 
MSN Search - Answers from Encarta provide access to more information on the keyword you typed in.
Meta Search Engines - Compiles results from a variety of places, all in one
Ixquick Metasearch - Ixquick knows which search engines can handle your keyword or phrase inputted, as well as boolean logic.
Other Internet Search Tools
Foreign Search Engines
Spider's Apprentice : How to Use Web Search Engines