You can take the guided tours or go for the self tour option. It is bustling with tourists, literally bus loads of them. The grand rooms from where war strategies were formulated, the exquisite grandeur of the hall of mirrors where statesmen were entertained, amongst other exhibits, is all breathtaking. In summer, there are music concerts in the large sprawling, meticulously-maintained gardens, as well as musical fountain shows - check site for details. It's a day trip out of Paris, and a history lesson that's well worth it. As always, more pictures than was necessary were taken on my last trip there.
All photos here - I was pretty much speechless and in awe throughout the entire tour.