Charleston (South Carolina) has a long history that is reflected in the colonial buildings. Long it has been one of the major cities in the USA. Nowadays it is a real pleasant city.
Chicago, on Lake Michigan, with nick name The Windy City, is one of the largest US cities. The Sears Tower is one of the tallest buildings in the USA.
Grand Teton National Park is a great park not far from Yellowstone with similar wildlife, but without the geothermical experience.
Las Vegas is the show and gambling capital of the USA and the Western world. The city is featured in many, many movies and TV series. Las Vegas is a desert city with water coming from Lake Mead.
The Las Vegas strip is the best known with casinos, fancy hotels and top-class resorts. You can also find the Eiffel Tower, Little Venice, a Pyramid and Lady Liberty here. Of course you can get married here with Elvis Presley as your witness.
Los Angeles (aka. City of Angels) is the 2nd largest city in the USA and has a lot to offer, including great shopping (a la Pretty Woman), Hollywood, Venice Beach and sports (L.A. Lakers).
Miami Florida is one of the main economic centres of the USA. It also has a world-famous beach and the best weather. Cuban and Puerto Rican influence is felt here, for example Miami Sound Machine. For many this is the starting point of a great US vacation.
Monument Valley is a desert with few small, steep rock formations in the shape of monuments. The area is a "classic" and a must-do in the Western USA. Of course it is featured in many movies...
Nashville is the second largest city in Tenessee and the heart of Country Music. Of course you should listen to the music that inspired so many and visit The Country Music Hall of Fame.