If you have an interest in beer, Bamberg (a bit north of Nürnberg) is worth a visit. Lovely old medieval city (UNESCO World Heritage site) with a bunch of old churches -- and the only place north of the Alps with the tomb of a Pope. Oh, and 10 breweries...

I'm not a fan of the Nürnberg Christmas Market -- too big, too much repetition and too much mass produced crap. I much more enjoy the ones in smaller cities and larger towns.

If you don't want to drive there are some decently priced German rail passes that will get you to most places. And Salzburg is considered "Germany" for rail passes.