Hi Extreme_Warlock,
Stuttgart and Munich are both nice cities. However, If you are traveling with the family, I would suggest staying near Lake Constance. Here at the lake, you can enjoy fun outdoor activities and bike tours. There is plenty of
hotels and B&B's in the area, and I think your family would enjoy it here.
Also, both
Stuttgart and Munich are within two hours of the Lake, so it could also be a day trip if you don't fancy staying in the area.