MGM Fantasmic is a must see. We never miss this light, stage, fire, water, and firework display. It is our number one must do. It may be to intense for younger children, although my DS5 has seen it 4 times in the last 4 years and loves it.
If you like animated movie charaters then the MGM motor car parade has a lot of them. We got some great photos last year of this parade. We viewed it around the exit side of Indiana Jones.
The AK Mickey's Jammin jungle Parade has some of the original characters. We also have veiwed this in Africa by one of the shops can't remember which one.
It is hot in the summer but just remeber sun screen and water are your friends. We usually go in July but have been in early June.