Days 1–2: Magic Kingdom & Universal Orlando
Day 1: Magic Kingdom, as in "In One Day". But on Day 2, slam through the highlights of the Universal parks with a 1-day, 2-park pass. In the morning, see Islands of Adventure, including the new Skull Island: Reign of Kong, as on the second day of the 2-day plan, and fill the afternoon with Universal Studios. Don’t neglect some of its popular rides—Transformers: The Ride—3D and Harry Potter and the Escape from Gringotts in Wizarding World of Harry Potter—Diagon Alley. Exploring that area will more than complete your day, but if you still have time, fill up on the sarcastically named dishes at Fast Food Boulevard in the daringly whimsical Springfield addition.
Day 3: SeaWorld, Disney & a Taste of “Real” Orlando
If you have small kids or you need something more subdued today, then SeaWorld Orlando, with its many marine animal habitats, isn’t as exhausting as Disney. That could take a whole day if you saw every little thing and stopped to smell the flowers (and fish), but you can see the highlights in 4 hours, and you only have 3 days, after all. So cram a secondary Disney park into your afternoon and evening. Epcot is a fine choice (see Day 2 of the "In Two Days" itinerary for a good plan), but Disney’s Animal Kingdom’s wildlife walking trails make a nice, easygoing complement to a morning spent at SeaWorld, and it’s open later than SeaWorld, too. If you exhaust Animal Kingdom and don’t want to see Pandora aglow, spend the night at the shopping-and-dining zone of the refreshed Disney Springs or go out into “real” Orlando for the Vietnamese culinary delights of Mills Fifty downtown.