Universal Studios if you're a big movie buff and definitely Sea World if you love sea creatures of all kinds are a definite must IMHO; as we always take the time out for seeing these great places when in Orlando as well as WDW (their rides and shows are awesome). Also, there are smaller scale attractions that are great way to spend half a day such as Titanic Ship of Dreams, Orlando Science Center, Wonderworks, Ripley's Believe It Or Not, Guiness Book Of World Records, Gatorland, and Splendid China to name a few. So, there are always other fantastic alternative things to see/do whenever you're on vacation other than WDW. Hope this helps some!