![enter image description here][1]

[Tiger - the US Census Bureau GIS data][2]. Covers the US only.

* Municipal and state boundaries
* Cartographic maps 
* Street maps

From my personal experience, the data is comprehensive, accurate and well-formed.

Last update - 2011.

  [1]: https://i.sstatic.net/U3NLB.png
  [2]: http://www.census.gov/geo/www/tiger/