I guess it is very much a question of personal taste! So go and have a look at the ones that appeal to you the most from looking at pictures. I personally would say AKL (where there is actually a lot to do: see the animals, at night even with night vision goggles, take the culinary tour or the art tour, have a meal, take part in the childresn activities...), WL and Poly. I have never been to any of the Epcot resorts, but would love to check out the Boardwalk on my next trip.