I have been to Duxford three times... not matter where you're from, you simply HAVE to go there. Had a 'tour' inside Sally B the first time and every time I'm in absolute AWE what they are restoring there and what they have in airworthy condition. Just imagine, you visit on a boring weekday, overcast sky and you see a Blenheim overhead. Unforgettable. Then you just pay your admission and wander through the hangars. Restauration in progress of a Beaufighter, Ju-52, Gladiator, a wrecked Zero in parts, just having been brought in. Fantastic.
The American air museum is awesome, B-17, B-29 and B-52 inside a massive hangar and a memorial to all American airmen who have fallen in WWII in the European theater.
And the land warfare hall is also great, with some recently acquired stuff from the Czech republic, including a Scud missile launcher.
Best moment ever was when I visited Duxford after having been to Mildenhall. Back in 2000 it was I believe. The battle of Britain memorial flight was based there for the weekend. Ever seen two Spits, a Hurricane and a Lancaster starting up their engines simultaneously?