Owl & Mouse (U.S. and World Geography) - Maps and Map Puzzles

MapQuest (Worldwide maps plus driving directions from one site to another)

Yahoo Maps (Just enter street address)

National Geographic Mapmaker (Customize and edit maps)

World Atlas 

Perry-Castaneda Library Map Collection (Maps arranged by continent; U.S. historical maps; Links to outline maps)

Trucker's Guide to Maps and Mapping (Tons of map links!)

Outline Maps

World Factbook Country Maps

Blank State Outline Maps

Infoplease World Maps

The Map Library (World Maps)