This country is full of jaw dropping places to see. I seem to be attracted to the Rocky Mountains the most. Lots to see around San Francisco California. Ride the cable cars around town, take a tour of Alcatraz, and the Winchester House is great. Head down the coast and drive the Seventeen Mile Drive near Pebble Beach. Further down the Pacific Coast Highway (PCH) is the Hearst Castle. Stop or turn around before you get close to LA.
Of course the Grand Canyon is a sight to behold and it's near the Hoover Dam and Vegas.
I didn't think anything could ever top the Grand Canyon, but last Fall I finally got a chance to go to the Sequoia National Park and see the General Sherman tree. I'm not saying it topped the Grand Canyon, but I did stand there for thirty minutes looking at it thinking it was impossible for something like this to exist. You can see Red Wood trees all over CA., but a giant Sequoia is a total different experience.
Another off the charts place to see is Dragonmans Military Museum just East of Colorado Springs. This guy is as cool as they come and he probably has as much military memorabilia as any museum in the country. A must see place. Check the website for days the museum is open.
If you're near Birmingham AL. there is the Barber Motorsports Motorcycle museum. Hundreds and hundreds of perfectly restored motorcycles. I've been to a lot of motorcycle museums and nothing even comes close to Barber.
Tombstone AZ is a fun place to visit. The wife and I rented a cabin out in the desert for five nights and explored the whole area. Don't forget Saguaro National Park near Tucson for all the cacti you'll ever want to see.