http://www.monoprice.com/products/product.asp?c_id=108&cp_id=10841&cs_id=1084101&p_id=5553&seq=1&format=1#largeimage This is a Ultra cheap table I recently bought, and I have no trouble with it. its a graphics tablet, large work area and programmable "areas" to open apps or menus. Works great in Photoshop and Zbrush.

I used to work for the Government as a cartographer. One issue with commercial based maps are the copyright controls. in order to keep competitors from stealing their work they purposely add or subtract roads. They know where the mistakes are and use them for copyright reference. on the other hand this is whats causes allot of trouble with GPS routers. One fix is to add a flag to the line data that could flag this and fix tons or routing trouble GPS devices have been having. Examples can be used for tonnage limits, rural routes, narrow streets, and low bridges. But because most maps are created using satellite or air photography overlays, that info is left out.

The U.S. Census Bureau's, Geography Dept. is in charge of creating and sourcing U.S. GIS maps. Most map's are updated during the census period when there are enumerator staff on location to send new road information. Some info is updated yearly when cities, and counties may update annexed land.

Files are created to be compatible with ArcView software and are free to download. Free maps are old, and can be as old as the last Census. In March, 2008 the Census Bureau will make the 2007 TIGER/Line Shapefiles available to the public. File formats include:
ARC/INFO EXPORT (.e00) format
ArcView Shapefile (.shp) format
ARC/INFO Ungenerate (ASCII) format.
These are NOT photographic maps, they have the look and feel of your standard GPS maps. They can be found here: http://www.census.gov/geo/www/tiger/tiger2006se/tgr2006se.html

This info is compatible with ArcGIS, But with the Ascii file its possible to create a opensource editor. I was using government software created to run under linux.