L. Britt and tuckergurl did this a while ago, and I put it away for a rainy day. Voila!
create your own visited states map
or check out these Google Hacks.
I counted the states that I've driven across, as well as places I've spent the night. Places where I've had airport layovers (Arizona, Minnesota and Texas) but didn't leave the airport don't count.
So, if you're desperately trying to figure out where Sleepy Hamlet, or Rockport, or Cowtown, or Steak City is, here's a bit of a hint. Good luck! ;-)