Broad Coverage

All the Web  

Google and Google Scholar (scholarly journal articles)

MSN  

OAIster (academic resources) (University of Michigan)

For Children

Ask for Kids (formerly, Ask Jeeves for Kids) 

Ivy's Search Engine Resources for Kids 

KidsClick 

Quintura for Kids 

Yahooligans! 

Subject Specific

Behavioral Health (State of Connecticut)

Directory of Health Organizations (National Library of Medicine)

Images (Google)

Information Science (DL-Harvest)

Law (FindLaw)

LexisWeb (LexisNexis)

NaturePreceedings

Science (Scirus)

Science (Science.gov)

Locate Other Search Engines

Librarian's Index to the Internet