My absolute favorite sound was always the peacocks calling from the trees. Sadly, they are gone.
The next favorite sound is the boat whistle....
Funny story about the EWP. On our first trip there way back in 2000, we had the camper in the 700 loop. It was our first night there. The kids were much younger and after the long drive from PA, we called it a night early. All of a sudden, LOUD music filled the air! It lasted to a good bit of time too! I couldn't figure out why Disney would allow someone to play such loud music at that time of night!

Took a few moments for me to realize what it was!