Thinking of doing a day trip to a nearby Chateau - what is your favorite? I don't think we want to go to Versaille but would like to go to one easily accessible by train. Nice grounds and gardens would be a plus - Giverney (I KNOW its not a chateau!) is an option too but when we went before it was SUPER crowded, lovely, but the tourists outnumbered the flowers by about 10 to 1!

Vaux-le-Vicomte would be about the greatest chateau - or at least fulfill the chateau picture in your mind - take train to Melun then taxi as there are apparently no public transit there from the station or anywhere

Or hop the one-hour TGV train to Tours to hook up with half- or full-day minibus tours that take you to some of the greatest of the great Chateaux of the Loire - like Chenonceaux or Chambord - some companies leave from the Tours train station - one is www.acco-dispo.fr - has been around a long time (not sure of exact web address)

Or take the train to Blois from where in summer special buses go to nearby Chambord castle in the countryside - the biggest and in many ways most monumental Loire castle though most find Chenonceau much more romantic

There is also Chateau de Vincennes that is on Metro line. Haven't been but it's on my list...there was a trip report here with someone's summary.

I suppose you could also say that the Louvre is a chateau.

Yes and there are Compiegnie (sp?) and Chantilly as nice chateaus steeped in history as well and easily accessed by train from Gare du Nord.

But i think Vaux-le-Vicomte, Chenonceau and Chambord are much more the chateaus etched in our minds eyes
my opinion only and the others are fine fine places - well Vincennes is more like a block fort, not a castle IMO

I haven't been to the chateau myself, but here's a link to information about the Forfait Loisirs for the Chateau de Fontainebleau which is a pass combining transportation and admission: http://tinyurl.com/6zmnrg.

I'd call Fontainebleau and Versailles super chateaus - more palaces than chateaus, which i think of as smaller country retreats

and since OP said no to Versailles, for some reason then Fontainebleau is in that league

But it is a great place with great gardens and sweet regional town around it and easily accessible by train - to the Fontainebleau-Avon station which is a mile or two on the other side of Fontainebleau the town than the chateau.
the Forest of Fontainebleau is great too, esp villages associated with the special school of art that developed there - like Barbizon but i believe they are difficult to reach by public transit.