You know, I took a survey in my department and, ready for this?... Animal Kingdom came out on top! Which is also my favorite park. As a Cast Member that visits the park on a weekly basis, I feel it has the most 'replay value'. For me it's so relaxing and rejuvinating. The fauna and flora are such a breath of fresh air. I love all of the 'hidden' trails, the amazing quick service locations, and the attention to detail.
The most amazing part of Animal Kingdom are the stories hidden inside of the attractions. My favorite story is the mural in the maharaja jungle trek. It's the parable about mankind and respecting the environment. It's amazing that so many people miss all of these types of things woven inside the park. I love the fact that there are animals EVERYWHERE. I think many people miss too much and would really appreciate the park if they slowed down and opened their eyes extra wide. Anyone have a guess as to how many individual animal attractions and exhibit areas there are at Animal Kingdom? 20? 50? 100? Keep going... and yet most people catch Kilamanjaro, the Oasis, and possibly the animals in the front portion of Discovery Island.
AK is by far my favorite park, which is why I try to visit at least once a week. For me, it's Disney Design and storytelling at it's finest, you just have to slow down and not walk right past it.