alt Hacker NewsI'd add the Henry Ford Museum in Michigan, and the Air and Space Museum (both sites). They are not as up-close-and-personal as some of the ones mentioned in the article, owing to the extreme number of visitors, but have some utterly unique and historic artifacts, like Thomas Edison's lab.
The US Smithsonian National Air and Space (NASM) museums are great.
For those that aren’t aware, one of the locations is on the Capitol Mall in Washington, DC and the other - the Steven F. Udvar-Hazy Center - is near the Dulles Airport in Dulles, VA.
The latter has the Space Shuttle Discovery, a Lockheed SR-71 Blackbird, a Concorde… and the Enola Gay.