Actually I wouldn't dare to travel to the United States. I have criticized their politics so often in online discussions that I fear they would send me back at the border. Also their laws are getting more and more restrictive ... in future they even want to know how many bitcoins someone owns who enters the country. A shame (at least in my opinion) what happend to the 'land of the free', but of course there are great landscapes and still a lot of friendly people (they are not responsible for politics).
I have entered the USA only twice - that was many years ago - when I was on my way to visit Mexico (and back). The border officials of the Atlanta airport were really unfriendly, and because of some of their arbitrary acts I nearly missed my return flight to Frankfurt.