The SR-71 Blackbird at the Udvar-Hazy Air and Space extension out by Dulles airport. With Imperial War Museum Duxford, this is the most impressive collection of aircraft I've ever seen. And the planes at the Air and Space extension are in much better condition than the planes at Duxford.
The final flight of this SR-71 was from L.A. to Washington. It took 64 minutes.
Read about the experience of flying the SR-71 here.