Google http://www.google.com/
Dogpile http://www.dogpile.com/
Yahoo http://www.yahoo.com/
Ask http://www.ask.com/
Nettrekker http://middle.nettrekker.com/subject
Clusty http://www.clusty.com
Excite http://excite.com/
Hotbot http://www.hotbot.com/
Metacrawler http://www.metacrawler.com/
MSN http://www.msn.com
Factbites-crosses a search engine with an encyclopedia http://www.factbite.com