I agree with every one of those suggestions. The hot ticket right now is the Museum of the American Indian (hate that name). But if you have never been in the Capitol before, I must tell you that you need to walk into the Rotunda and spend an hour or so. I have been to DC so many times, usually on lobbying stuff for the Union, that I get a bit jaded. But one simply cannot walk into that Rotunda and not get a chill.