I'm curious what are your favorite days trips from Munich, other than Salzburg, Dachau and Neuschwanstein?
Second vote for Regensburg.
Hi, Salzburg and Ingolstadt
Right off the top, Oberammergau, Garmisch-Partenkirchen (Zugspitze), and Mittenwald come to mind. You can take the S-Bahn (S5) or the BOB (Bayerische Oberlandbahn) out to Holzkirchen and see the resorts of Schliersee, Bad Tölz, etc., in the foothills of the Alps. Even less know, but interesting, is the km long castle high on the ridge overlooking the Salzach River in Burghausen.
Regensburg, about 1.5 hours north by regional trains. It is an UNESCO World Heritage Site for its medieval buildings. Wikipedia does a good job of describing it. http://en.wikipedia.org/wiki/Regensburg Along the same train route is Landshut, Bayern, about 45 minutes north of Munich. Castle, St. Martin's church and nice pedestrian zone. Great webcams if you are interested. http://www.landshut.de/top/webcams/webcams.html
Rotenburg is an easy train ride. Fairly inexpensive using the Bayern Pass