This won!

USAUSA, a photo by Ape Lad on Flickr.

Thanks to everybody who voted for this design! It's on sale at woot at right here.
If you haven't swung by the site lately, they're printing shirts on American Apparel again for one thin dollar more, but only on the first day of sale.
I don't recommend placing pins in this shirt to represent the states you've visited, especially if you're wearing it at the time.