The Petite Trianon which is on the property is small and lovely. It's a hike to get there so wear comfortable shoes or take the tram which costs a couple of euros. Marie Antoinette's "peasant village" is also interesting, especially if you have children. Even my 15-year olds enjoyed seeing though.
WAY too many people being hearded like sheep through the castle to be able to actually enjoy it...if I went again I wouldn't go inside and instead spend more time in the beautiful gardens....which are FREE :)
The Palace of Versailles was the principal residence of the French kings from the time of Louis XIV to Louis XVI. Embellished by several generations of architects, sculptors, decorators and landscape architects, it provided Europe with a model of the ideal royal residence for over a century. One of 37 World Heritage Sites in France!