• Huge Meta-List of Maps and Gazetteers: Odden's Bookmarks
• Large collection of scanned maps:  PCL Map Collection or  The Map Guide
• Scanned Images of Historical Maps: David Rumsey
• Printable Boundary Maps (and other maps of interest):MSU Map Library Printable Maps
• World Petroleum Assessment, Data and Interactive Maps
• Placenames Worldwide: NGA GeoNet Names Server
• Interactive roadmaps, US and Other Countries (and calculate mileage) MapQuest or Maporama
  
• Getty Thesaurus of Geographic Names
  

• Detailed Topographic Maps (also helpful for finding lat/long coordinates of anyplace in the US) TopoZone
• More topographic maps, aerial photographs, and satellite imagery at Terraserver or GIS Data Depot
• NationalAtlas
  
• Scanned images of Historical US Maps: Library of Congress American Memory
• Geographical Names Information System: from the U. S. Geological Survey
• Aerial photos and satellite imagery: TerraServer or GIS Data Depot or UC Berkeley Catalog
• State Geological Surveys

Michigan & Great Lakes

• Michigan Interactive Mapper (primarily road maps with points of interest)
• MSU Remote Sensing & GIS Interactive map of Michigan (includes 1998 infrared aerial photographs)
• Local Government Interactive Mapping Sites
• Local Government Interactive Property Search Sites
• MI Natural Features Inventory (MNFI)
• Great Lake Surface Temperature
• Great Lakes Bathymetry Maps
• Great Lakes Map Gallery
• Historical Weather Data Michgian Automated Weather Network (MAWN)
• Michigan Recreational Boating Information System
  

Geography Tools

• Calculate distance between any two lat/long points
  
• Abbreviations & Acronyms in GIS, Cartography and Remote Sensing: UC Berkeley Dictionary

Select Regional Sites

• Africa Data Dissemination Service
• National Atlas of Canada
• Geological Survey of Canada
• Canadian GeoNames
• Statistics Canada
• Canadian Driving Maps
• LANIC -- Maps of Latin America
  
• INEGI Mexico Census Information

GIS Datasets

• Michigan Geographic Data Library
• MSU Remote Sensing and GIS (RS&GIS) Data and Products
• GIS Data Depot
• Geodata.gov
• Geography Network
• USGS's LULC, DLG, DEM and other datasets
  
• US Census data in MapInfo or AtlasGIS formats: SEDAC's US Census Data for GIS
• Census Boundary Files in ESRI's .e00 format or .shp format: U.S. Census Bureau
• The EPA's Clean Air Markets Program
• The FCC's Geographic Information Systems Download Page
• The U.S. Fish & Wildlife Service's NWI Datasets
• The U.S. Fish & Wildlife Service's State Download Page