Great question. My answer is:
1. Magic Kingdom- Fittingly, I like this park the most because it is the most "magical" in my eyes.
2. Animal Kingdom- I just think this is a cool park and I think it will continue to grow in the next decade or so. I can't wait for Expedition Everest to open. It looks like it'll be a lot of fun.
3. EPCOT- As I've gotten older, I have continued to have a growing appreciation for this park. I love Spaceship Earth, Test Track, and I can't wait to go on Soarin' and Mission:Space the next time I'm there. The countries are great to walk through and I hope to actually sit down and eat in Italy one day.
4. Disney-MGM Studios- This used to be my second favorite, but more and more I've come to not like it as much as I once had. I like Rock 'N' Roller Coaster, I love Star Tours (but it needs to be updated), and I love the Muppets 4-D, and think Fantasmic is a great show, but that's about it. I'm not a fan of Tower of Terror. I love the theming of the park, but I would like to see the Indiana Jones ride actually come to the park. I could care less about the motor cars stunt show. I can see that in non-Disney parks. I want something unique, other than what is already there.