Dresden is worth a visit
Don't go anywhere in the Czech Republic, it's pretty stuffty
Even Prague
Neuschwanstein is slightly disappointing depending on what you are expecting
The national history museum in Berlin is climaxic
Bring your student ID everywhere you go, "kids" under 18 get huge discounts for a lot of this stuff.
The "Victory Tower" in the middle of Berlin's huge park thing is worth climbing up, also they have candy