Canada, National Atlas Information Service (NAIS); responsible for the development and maintenance of an authoritative synthesis of the geography of Canada
Cartographic Images Home Page Ancient, early medieval, late medieval, and renaissance maps and links to other catographic web sites.
Geographic Names Information System - Online Data Base Query Form; U.S. Geological Survey - National Mapping Information (This one is GOOD!) contains information about almost 2 million physical and cultural geographic features in the United States.
Gold Bug - Commercial site with a couple of free downloads