Schoenbrunn Palace, otherwise known as the Austrian version of Versailles.
Cool little place actually, but you have to put these places in perspective. Granted the living spaces were huge, and they could throw a hell of a kegger in the ballroom - but they also had tons of administrative space in these places.
It was definitely a little more low key than Versailles - not quite as big, gardens not quite as over the top, etc - but it was also a lot of fun - complete with zoo, and garden maze.