Discovery School-lists lessons by lesson names. Perhaps the best feature of the page is the "favorites" section which provides clip art, brain boosters, a puzzle maker for at least 7 different types of puzzles, and study starters.
http://school.discovery.com/lessonplans/

The Lesson Plans Page- Searches are simplistic and easily guide you to the proper subject matter and grade. Once you find the right area of focus, the site also conveniently divides up your subject matter into different categories, eliminating the need to search needlessly through a number of lessons.
http://www.lessonplanspage.com/

Educator's Reference Desk- Not as an extensive grouping of lesson plans as other places, but an extroadinary group of resources for educators in a number of areas including assessment, family issues, counseling, technology
http://www.eduref.org/

Teach-nology-lesson plans, games, worksheets and more
http://www.teachnology.com/

Columbia Education Center-good lesson plans listed, but hard to have to wade through them all as there isn't a search process and they are only listed by name. One good aspect is the secondary list of resources for more lesson plans
http://www.col-ed.org/cur/

The Webquest pages-plethera of webquests listed and categorized by grades, subject matter and success.
http://www.webquest.org/

The edhelper.com-
http://www.edhelper.com/

Teacher's net
http://teachers.net/lessons/

Gateway
http://www.thegateway.org/

Maps, Geography, Culture and Travel:
USGS Learning Map Wizard
World Factbook and Atlas
National Geographic
National Atlas of the United State