I used GeoCommons.com and an office real estate report from Colliers International to visualize data on vacancy rates around the U.S.
We recently obtained a bunch of information (7 megabytes worth) from the USGBC and GBCI covering all sorts of metrics about certified/registered projects such as state, project type, LEED product type (Core and Shell, Commercial Interiors, New Construction), LEED version, registration date (2000-2008), certified yes/no, certified date, etc.
The first visualization I could obtain without much effort is the number of LEED Accredited Professionals by state. California leads the nation with over 11,300 LEED APs. New York comes in second with over 4,900 LEED APs.