IOA has some of the best coasters in the Orlando area:
You have the Hulk ( the most visually popular ) and the Dueling Dragons which is 2 different inverted roller coasters in one.
To add to the appeal, there is the Spiderman Ride which is by far one of the greatest rides I have ever encountered. It's not a roller coaster but it is a 3D thrill ride that is different than most 3D rides. There is also a few good water rides including the Jurassic Park ride.
Disney has some good coasters too. Rock and Roll Roller Coaster is one of the coolest roller coasters I have been on and definately worth the wait. Exepetion Everest is a new one at AK and is another worth the wait. At Disney would will also have Tower of Terror which is an elevator drop scenerio.