Hmmm...I haven't been to all the parks listed, so I am going to have to make a partially informed choice.
I am going to go with Epcot. Epcot appeals to the scientist and culture lover in me. Plus, I just love that my home DVC resort is in within walking distance of the International Gateway. (Gotta love the BWV!!) I'd put DL/MK as a close second. MGM/AK/DCA bringing up the rear. I haven't been to any of the Disney resorts over seas yet. There is something about every park I have been to that I enjoy.