Best European City to Visit in December

We spent 10 nights in Paris a few years ago, arriving a few days after Christmas. It was beautifully festive in a way that was not over the top, as you often find in the U.S. it was bitterly cold while we were there, but there are so many indoor activities you can do to get warm. We had our 20 year old daughter with us and she had such a great time. We rented an apartment and that was such a great decision for us. Hotel rooms are so small, and the apartment allowed us to prepare some of our meals. That saved us a lot of money.

Because you'll be in Austria, and presumably if you're skiing, cold weather doesn't bother you... how about Munich or Vienna?

Paris... my 22 yo son loves Paris. It has so much to offer for every age.

Vienna... it's very romantic but also cool enough for your sons. There is great night life, especially around the university. Alternatively Munich for the exact same reasons. You could also combine Salzburg and Munich...

Vienna,Vienna! The Christmas Markets are wonderful and there is much to do and see for all of the family.

A few years ago my husband and I were in Germany in December and visited a handful of Christmas markets. My favorite town + market hands down was Nurnberg. Absolutely enchanting, and the market wasn't overrun with imported kitsch like some others we've been to. Salzburg in December is also really nice (but didn't like the market as much).

Vienna, Munich and Salzburg are all great choices. The first 2 have the best Christmas markets.

Another vote here for Vienna.
Or Prague- also has a great Christmas market and lots of places for the lads to enjoy.