I was impressed by the disney website. You can see each attraction at the theme parks, choose your favorites, then print off itineraries.
We went in January once. There weren't many lines. Very enjoyable. We did not go to the water parks however. It was a bit too cold. We were there for 1 week. It got to 80 degrees one day, so that was the day we spent at the resort (Carribean Beach Resort). Enjoyed the sandy beaches & rented pedal boats.
I second the suggestion on taking breakfast to eat in your room. We took cereal. There was milk in the fridg in our room. I've also heard they sell milk in the sundries section at the food court.
The last time we were there I remember really enjoying dinner at MGM at the 50's Primetime Cafe. Also the Muppet 3D thing was fun. At Epcot, the Living Seas was neat. Didn't care too much for the Spaceship Earth attraction. At MK, we loved the Haunted Mansion and Big Thunder Railroad.
Have fun!