This is probably of very little interest to anyone except me. I've got different bookmarks on different PCs and keep forgetting what I've got where, and indeed why...
http://www.historicaerials.com/ Awesome mapping site. Where there's historical data it's a bit like old-maps and GE combined.
http://nationalmap.gov/viewer.html Some DEM. Can't remember if I've ever got this to do anything useful.
http://www.viewfinderpanoramas.org/Coverage%20map%20viewfinderpanoramas_org3.htm More DEM. This is actually useful.
http://www.railway-technical.com/newglos.shtml UK/US translations, for such times as when I try and pretend I know what I'm on about.
http://research.nprha.org/Lists/All%20Site%20Databases%20%20Lists/Standard%20View.aspx Not sure why I've bookmarked this. Northern Pacific stuff.