Salzburg and the castle are brilliant (I think Where Eagles Dare was filmed there)
You can even do a Sound of Music tour whilst you are there, I recommend being drunk before undertaking this though as it certainly helps.
You can pop across the border into Bechtesgarten and go up to the Eagles nest (Hitlers hide out) and then take a trip across the Koenigsee, also in Germany although only just is Neuschwannstein, the fairy tale castle place built by a mad, gay, Wagnerian Bavarian King.
You've seen it in Chitty-Chitty Bang Bang and its definitely a highlight of Europe.


Innsbruck is lovely, and a good place to base yourselves if you want to go into the Mountains hiking, or even ski up on a glacier.
Been to Vienna a few times. and although it's kinda pretty, I've hated it everytime.