visited 32 states (64%)
Create your own visited map of The United States
I don't count states where I only changed planes or otherwise stopped while flying by air without leaving the airport (Hawaii, North Carolina, Idaho). I do count states through which I've traveled by train if I ever got off the train regardless of whether I left the station. This means that I don't count Indiana
Update, 10:35: *headsmack* I forgot about the Millennium Philcon!
I count states within which I've driven or ridden in a private vehicle, which means I include North Dakota even though the visit was being driven back and forth between Grand Forks and Winnipeg. Arkansas also just barely counts, as we popped over to West Memphis on the road trip to/from the December 1993 SMOFCon in Lexington KY because the gas was cheaper there before heading south.
My world travels are less impressive.
visited 9 states (4%)
Create your own visited map of The World
Again, changing planes only without going groundside doesn't count, so I don't include New Zealand. The only country that has hosted a Worldcon that I've not been to is Germany. The most odd-ball (and least visible at this scale) country that I can include here is the Channel Islands, where I attended a SMOFCon in 1993.