I've been to both twice, and I'd definitely go back to Universal before Disney. At Universal, you're walking much less between attractions. Be sure to go on the Jurassic Park River Adventure, and if you got the balls, the Incredible Hulk roller coaster. That thing is a beast. It shoots you 60 storeys into the air, and then a monstrous double roll. Even more cool, when you stand beside it, it sounds like the Hulk's roar when the coaster goes by!
I loved NASA, Seaworld was boring. Waterparks are fun if you don't want to waste time driving out to the beaches.
Im jealous. I want to go back.