How many have you visited? Passing through a state doesn’t count for this list.
My total as of 18 Dec 2011: 26 states + Washington, D.C.
List of States
Alabama – fall 2005 to see the Gators vs. Alabama (Urban Meyer’s first year, the spread offense gets crushed, as do Tyrone Prothro’s lower leg bones)
Arizona – spring 2008 for a conference in Phoenix
California – first couple times were to San Diego in 2007; later, L.A. in 2010
Colorado – visited friends in Boulder, spring 2010, with a side trip to Casa Bonita in Denver, which is a real Mexican restaurant, not something South Park invented