My personal top four:
1. Kennedy Space Center. Prepare to bring your credit card. I wanted everything I saw - toy space shuttle, NASA gear, Mercury, Gemini, and Apollo stuff, videos, and books. Wow. Then (if you time it right) you get to see a shuttle on the launch pad. Fantastic.
2. Busch Gardens. Technically not Orlando, but only a little over an hour away and easy to find. We found it better than Magic Kingdom for kids. Land of the Dragons was brilliant, only we didn't get to it until near closing time.
3. Magic Kingdom - fireworks and parade. I know it's a bit twee, but I really enjoyed it. After spending my life seeing pictures on TV, to actually be there was great. To get in the mood, go straight to meet Mickey, Minnie, et al. It sets you up for the day.
4. Shopping. Take a trip down International Drive, although we didn't find Belz Outlet Mall to be that great - there were better ones. If you like your clothes designer, then this is heaven for you. If like me you are not fussy about the brand then you can also find cheap and cheerful stuff.
Overall, a fantastic holiday experience. Orlando is a place I believe you have to visit a number of times before you get to do everything. Two weeks was just not enough.
Quick Tips:
Hire a car. Turn on the airconditioning five minutes before you need to drive. Also, we flew in at night and still had to get to our apartment. We actually retyped the directions given, using the biggest font we could find. This made it easier for navigation. Also, be prepared to live by the road numbers, it is not like being at home where you generally know where you are going.
Want a free ticket to the theme parks? Then go to a timeshare presentation. You get these for attending, and who knows, you might even buy a timeshare.
Bring your own water to all theme parks and lots of sunscreen. If you have children try to find a cap with the material hanging down over the neck (like the French Foreign Legion have). Make sure you have it before you arrive because they don't sell them in Orlando.
If your child is still stroller size then bring the stroller (great for hanging stuff on and your child will get tired in the heat).
On entering the theme parks, head for the furthest point and then work your way back.
Best Way To Get Around:
The car is king in Orlando, and it's actually quite easy to get around, even for someone like me who is used to driving on the other side of the road. The roads are big and people don't drive as fast as they do in Europe.