Cartograms

A Cartogram is a map that modifies the shape
or size of a boundary to represent the data values. They are
contiguous and non-contiguous. The spatial geometry is distorted to reflect a certain theme. For instance, a country's size can be distorted to reflect its population or its annual oil consumption. An advantage of a cartogram is that small enumeration units with high attribute values that would be hidden on a conventional equivalent projection can be readily seen.

Examples:

http://i2.photobucket.com/albums/y25/photoholder/VA-GovCartogram.jpg

http://www.kieranhealy.org/files/misc/cartogram.png

http://www-personal.umich.edu/~mejn/cartograms/energyconsump1024x512.png