Elementary SuperSites:
MARVEL!
KidSpace @ the Internet Public Library
International Children's Digital Library
On-Lion for Kids (NYPL)
StoryPlace
National Library of Virtual Manipulatives
Reference Section
World Book Online

Middle School SuperSite:
MARVEL!
TeenSpace @ the Internet Public Library
National Library of Virtual Manipulatives
Reference Section
World Book Online
MSN Encarta

High School SuperSites:
MARVEL!
The Internet Public Library
Library of Congress
National Library of Virtual Manipulatives
Reference Section
World Book Online
Wikipedia

Teacher SuperSites:
Reference Section
Educator's Reference Desk
The Gateway
The New York Times Learning Network

Librarian's SuperSites:
Librarian's Resource Center
Internet Library for Librarian's
LibrarySpot

Family/Parent SuperSites:
PBS Parents
Parents Center

World Book Online
Discovery Streaming

Easy Alignment, Easy Integration, Engaging Learning!
GeoGames (Grades 3-5)
National Geographic Kids (Grades 2-6)

Middle School SuperSite:
World Book Online
Discovery Streaming
MSN Encarta
Google Earth Explorations

Easy Alignment, Easy Integration, Engaging Learning!
The Futures Channel

Go Big - or go far from home!
ThinkQuest: Challenging, 21st century projects!

High School SuperSites:
World Book Online
Study Guides and Strategies
Google Earth Explorations

Teacher SuperSites:
PBS Teachers: If you only subscribe and follow one teacher's community site, make it this one... sign up to get their newsletter via email (monthly).
Education World: In terms of thinking about almost anything relating to education, this resource data-base is alive with activity that help keep teachers (school administrators, board members, parents, community members too!) engaged and enabled as educational innovators.  The best resource online for busy school-community members that also serve as school leaders (we hope that is many in our school-community).
Discovery Education Classroom Resources: Absolutely stuffed with exceptional video and instructional resources and tools.  Our ES school pays for the Streaming Media and instructional tools content; but all teachers, students, and parents have access to wonderful educational resources through Discovery Education and Discovery Educator's Network (DEN).
4Teachers: Lots of web resources arranged by grade and subject.
Thinkfinity: One of the most funded efforts to offer free guidance and access to quality on line educational resources.
Google Earth Educators:  Offers a real chance to transform learning in 21st century ways with great technology tools (maps, but so much more connected or possible).  Ask me for ideas or I would be glad to help construct a meaningful lesson in any subject that integrates Google Earth in a powerful way.  It's that versatile and engaging!
Scholastic: Teachers: Primarily a K-8 resource and an example of best-practice online education resource for K-6.
Discovery Education School Resources
NYTimes Learning Network: Primarily a 7-12 resource, excellent range of resources, again so versatile and engaging that almost any learning subject can be enhanced by resources in this data-base.

OTHER SUPERSITES:
Free Mac Tools
Eduhound