When I went to Europe with my high school orchestra, we stayed primarily in Austria. It was, in my opinion, the most incredible place I"ve ever been. There are hundreds of sites to see, and Vienna is one of the cleanist and friendliest cities ever. Be sure to check out anywhere in Austria if you get the chance.
I also got to spend a day in Venic, Italy, and I highly suggest going there as well.
Enjoy yout trip!