Versailles is my birthplace, but I would have to agree, there is not much there besides the Château. The "Rive Gauche" district (to the left when facing the palace) has been preserved better than the rest of Versailles and has buildings per the original urban plan. Louis XIV gave free parcels of land to all, provided they did not build buildings higher than 2 stories, most dodged this restriction using the distinctive mansardes (garrets).
The Trianon and Marie-Antoinette's pretend farmhouse are technically not part of the Château itself, but well worth visiting. Versailles is famously bourgeois, so you can people-watch the prototypical "BCBG Versaillais" clad in a loden jacket (for men) or Hermes scarves and pearls (for women).
In summer, they run the historic fountain and waterworks, with baroque and classical music concerts such as would have beenplayed in the Sun King's day.