I was playing around with the World Map library and doing some googling when I found this really cool tile set called CyclOSM. Unfortunately, this tileset isn't in Snap! natively, so I wrote some code to view & use it, and it should work for most other tilesets, too, if you can fit their formatting in the way that Snap! understands (see the maps.js file). This project requires JavaScript to be enabled to use.
Cool! 