It's a little expensive, but there's always something fun to do. Most of us go to re-ride some of our favorite rides. My dad went to just walk around and get exercise and look at things.
Epcot center also has a ton of live entertainment including live bands and performers. They also have events with foods from around the world, flower or butterfly festivals, and more.
For what it's worth, my impression of Disneyland (California and Tokyo) wasn't nearly as good. They were fun, but they didn't have enough stuff to keep me coming back. But then, I don't live there, so maybe there's more to it. Those parks did have one thing that I wish Florida had: They change some of the rides once in a while to match another theme, such as Nightmare Before Christmas on the Haunted Mansion or "Hyperspace Mountain" (Star Wars) on Space Mountain.
I have to say... You're the only person I've ever heard say they went to Disney once and have no interest in going back.