My favorite would have to be All-Star Movies... not because of the layout, the rooms, etc. Simply because that is where my kids first discovered the Magic of staying on property.
The first time we took the kids and stayed on property (our 1st trip with them we stayed off property), I let my kids pick out the resort. They would have been 6 and 4 at the time. I was scrolling through pictures of the resorts on the Internet. When we got to one of the 3-story tall Buzz Lightyear at All-Star Movies, my son's jaw dropped. Looking into his eyes, I knew that is where we had to stay. We requested a room in the Toy Story section.
They loved everything about the resort, the pool, the large characters, etc. We stayed there again last Spring (when they were 8 & 6) and this time were in the 101 Dalmatians section. They loved it again.
We have visited / eaten at several other resorts with the kids including the Grand Floridian, Polynesian, Contemporary, Animal kingdom Lodge, Wilderness Lodge, Coronado Springs, Caribbean Beach. I mentioned to them recently that we might stay somewhere else the next time we go. They were stunned, and don't want to switch.
My opinion is that (although my wife and I love Disney) that the trip is for the kids. If they insist on staying at All-Star Movies again, we will definitely do so.
(If it was up to me, my first choice would be Poly. I stayed there before I was married / had kids and would love to do so again.)