Of course, I'll open this question up on Storm2k, with a few more choices...
However, the exact Wii question goes as such: How many U.S. states have you visited? 10 or fewer or more than 10?
(This question was restricted on Wii to only U.S. voters)
Here were the results...

I didn't get a picture of it, but females were more frequent travelers than males, but only by a few percentage points.
Here is the state-by-state break down. The brighter the pink, the more people who voted "10 or fewer" and the brighter the green, the more people who voted "more than 10." Grey states identify states with close results...

By the way, I've visited 25 states, not including the District of Columbia and Guam.