Sound of Music
This city is certainly has a large base of Tourism surrounding the movie "Sound of Music". They have tours daily and places around the city are easy to pick out. Even though most Austrians don't like the movie itself, it's a great tour and the Austrians support tourism. Go on the tour to find out why.
Insider Tip:Try the Mozart balls.... Also, go to the top of the Hotel Stein at night, there is a restaurant/ bar, you need not pay, just walk in. Great pictures from the balcony. Also, amazing pictures from the Mozart walking bridge as well.