When using online services to provide the baselayer for your app, you depend on an Internet connection to be able to see and develop anything. I was looking for a clean baselayer that I could serve locally on my laptop.

I found World Light (world-light.mbtiles, 1220MB) from the great folks at MapBox.

It’s in MBTiles format (full spec, based on SQLite, for easy offline use).

Recommended tileservers are Tilestache (Python) and tilelive.js / TileStream (both for Node.js)