Still catching up — the David Rumsey Map Collection announced last month that it has added over 550 new maps to its online collection.
You can get a list of all the new maps here. A nav on the right shows you the kinds of maps available, including national maps, physical maps, and atlases. As you make selections your search options narrow down further. You can also choose by place mapped, date, and cartographer.
Some of my favorites from these new maps include some wonderful renderings of the US from the early 1800s; constellations maps from 1824; and the “Ice Atlas of the Northern Hemisphere” (US Navy, 1946.) Each map page has a sidebar of information as well as basic zoom/pan controls. You can choose to buy prints of images or just export them. I exported the largest available images of one of the polar ice maps and, though it took a few minutes to generate, I was rewarded with a 9MB, very cool JPG.
Even if you’re not particularly into cartography, this site is worth a visit just for the artistic aspects of the maps. If you’re not sure where to start may I suggest Gilles Robert de Vaugondy and his Atlas Universel.