well what do you plan on doing during the day? Are you going to head out to parks until closing or do you come and go during the day?
If you're going to head out not to return until they kick you out of the parks, then breakfast is probably a good idea to eat in the room before you leave.
If you come and go alot or spend time doing other things like golfing, then i'd say lunch. You can get into whatever park is doing the Extra Magic hour for that day, ride the rides for a while, then come back and eat lunch, relax a while, and then go back to the parks, ride more rides, eat dinner in the parks or resorts, and then catch a nite time show.