Do you know of other good websites for map-lovers?
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David Rumsey Map Collection http://www.davidrumsey.com/
Map Gallery http://www.cartotalk.com/index.php?showforum=14
Ancient World Mapping Center http://www.unc.edu/awmc/mapsforstudents.html
Huge Resource - Berkeley Map Collection
These are good for OpenStreetMap-lovers:
MapBox (http://mapbox.com/) - for creating custom maps in the cloud using OpenStreetMap and other data sources
For historic maps:
I am maintaining a map site, all my own creations. Pretty in its infancy, but I hope you guys would like it: http://mapsnmaps.blogspot.com/
Mapillary - Crowd sourced street level photography that you can contribute to with using a smartphone or action camera. Uses OSM as a base map.
Lithuanianmaps.com - Here are, believe it or not, over 1,500 unique maps of the area covered by the historic, c17th century, Lithuanian region, which includes Estonia, Latvia, Lithuania, Belarus, Eastern Poland, Kaliningrad Oblast and Ukraine.