Hi Steven,
You have chosen a really fun time to visit Walt Disney World, although a very crowded time, so keep that in mind. I am not sure how many days you want to spend in the parks, but if you are only going a limited number of days during that week, I would suggest going during the week at the beginning of your stay since many locals will visit for the 4th and following weekend. However, if you are spending each day during your vacation, I would highly recommend getting to the parks early in the day as crowd levels during that busy week could fill the parks to capacity, especially on the 4th of July.
My personal favorite park is Magic Kingdom and the
patriotic feel will be in the air with special fireworks and shows. Epcot would be another great option especially in the American Adventure pavilion. Again, I want to stress that on the 4th of July, the parks have been known to fill to capacity and once they do, they will not let any more guests in. So, be prepared to get there early and don't hop from park to park, as you run the risk of leaving one park and getting to the next and it being at maximum capacity!
Have a magical time and let freedom ring as you celebrate our country's birthday!
~Allison L