I just visited the Air & Space Smithsonian museum, and it's 100% awesome-sauce! They had decommissioned nuclear missiles, a copy of the first wright brothers plane and the real Skylab space station, and so much more!
My favorite part of the Air & Space museum was the main level where they had the actual mercury, gemini, and apollo command modules! They were so cool! You could see every tiny piece of machinery and tools the astronauts had on their ship!
I also liked the apollo relics and machinery the museum had. They had the actual technology from the lunar modules! They even had a space catheter and toilet from the ships!!! And they were used!!!(And flushed) They also had actual epic shuttle engines! They were huge!