General Search Engines Commonly used Search Engines

AlltheWeb
A popular search engine.

Altavista
Provides you with both basic and advanced searching which offers powerful command driven search features.

Ask Jeeves
A popular search engine that offers natural language searching.

GO / Infoseek
A popular search engine.

Google
A well known search engine service providing a range of search and browse options.
               (Information Sheets & Guides - 
Google Search Engine - (PDF).)

Google Scholar
Google Scholar enables you to search specifically for scholarly literature, including peer-reviewed papers, theses, books, preprints, abstracts and technical reports from all broad areas of research.

HotBot
In one spot, you can now query the search engines FAST/AllTheWeb.com, Google, Inktomi and Teoma. Sadly, you can't search all at the same time.

Teoma
A relatively new but gaining in popularity search engine.

MSN.com
Search engine from Microsoft Corp.

Mamma
Claims to be the mother of all search engines.

Wisenut
A popular search engine.