The white mountains in New Hampshire are a must see and a short drive from Boston. The most beautiful and unique states in the union are, in my opinion, Tennessee and Arkansas. The drive from Phoenix to Flagstaff is incredible. Forget DC, really, not very interesting (unless you like to witness extreme class stratifications). But as a foreigner I suppose it is a must see. The urban ruins of Detroit are incredibly interesting. The Pacific Northwest is unbelievably gorgeous. Las Vegas is, in my opinion, only what's worst of America- skip it. New Mexico, if you can make it there, is pretty spectacular. So is Texas, and given its reputation around the world I would highly suggest seeing it. New Orleans is really cool, also, and will give you a view of America that is totally unique. Personally, though, my favorite part of the US is New England. New York State, in all its enormous glory, is also fantastic. Don't miss the Adirondacks. Try and stay out of Florida (unless you like swamps)- its where we keep all our old people.