The following is a list of places I've traveled to and the date of my first visit.  A visit counts as driving through and/or stopping off, not just getting a connecting flight through an airport. 

US States:
Alabama - 2001
Alaska
Arizona - 2007
Arkansas
California - 2002
Colorado
Connecticut - 1982
Delaware - 1988
Florida - 1988
Georgia - 1988
Hawaii - 2007
Idaho - 2007
Illinois - 2005
Indiana - 2003
Iowa
Kansas
Kentucky - 2005
Louisiana
Maine - 1993
Maryland - 1988
Massachusetts - 1993
Michigan
Minnesota
Mississippi
Missouri
Montana - 2007
Nebraska
Nevada - 2005
New Hampshire - 1993
New Jersey - 1983
New Mexico - 2010
New York - 1990
North Carolina - 1988
North Dakota
Ohio - 2002
Oklahoma - 2012
Oregon
Pennsylvania - 1992
Rhode Island - 2007
South Carolina - 1988
South Dakota
Tennessee - 2003
Texas - 2004
Utah - 2008
Vermont - 2000
Virginia - 1988
Washington - 2006
West Virginia - 2003
Wisconsin
Wyoming - 2007
Total: 

International:
Antigua - 2009
Aruba - 2009
Bahamas - 2005
Barbados - 2009
Bermuda - 2008
Canada - 2000
Cayman Islands - 2011
Curacao - 2009
Dominica - 2009
Dominican Republic - 2009
Germany - 2008
Italy - 2011
Jamaica - 2004
St. John - 2009
St. Lucia - 2009
St. Thomas - 2009