I'd go with the week after Labor day in Sept..no crowds, nice weather.
Oct is also great too & the first 2 weeks of Dec is empty but some days can get cold.
I prefer Dec because of the cooler weather and low crowds. But be warned, when I say cooler I mean cooler. Been there when there has been frost. Dec weather can be really chancy, need to bring shorts and t-shirts as well as fleece and long pants. No guarantee which you will need any given day.
I have never been in Dec or Nov, but my favorite months are Sept and Jan. Now I have started pushing Sept trips closer to the end of the month so I can take advantage of the food and wine festival and MNSSHP. I enjoy September becuase it is fairly empty and it is still hot/warm out for me...it is like an extened summer. No need to stake out a parade spot or Fantasmic spot two hours early!
Go in early November! I PROMISE, the weather is perfect and the crowds are light. You can also be there for Epcot's Food and Wine Festival which is not to be missed!
Weather in November is low 80's and dry. Weather in Florida doesn't get any better than November! Really!
We did a Thanksgiving trip to WDW one year, which was amazing, but crowded. Having lived here now through two November's it is always the month I suggest people visit.
I prefer Dec because of the cooler weather and low crowds. But be warned, when I say cooler I mean cooler. Been there when there has been frost. Dec weather can be really chancy, need to bring shorts and t-shirts as well as fleece and long pants. No guarantee which you will need any given day.