create your own visited states map
or check out these Google Hacks.
Three big holes: New York-New Jersey-New England, The Southeast (except for Georgia, where I keep going to CTIA shows) and the upper end of the great plains.
To be honest, I think I drove into South Carolina during a trip to Charlotte, just to say I'd been in South Carolina, and I've only been in Ohio long enough to drive from the Indiana border to I-275 on I-74, and then back into Indiania before crossing the Ohio river into Kentucky (or back on the reverse trip).
The map of visited countries is much more boring, since I've only ever visited Japan, Mexico (and only as far as I could walk from the San Diego border crossing), New Iceland (never left the airport), Australia and Canada.