Hi Victoria!
I recommend taking your son to Disney's Hollywood Studios. Both of my children, age 5 and 10, absolutely love that park.
Your 2 year old will probably enjoy Playhouse Disney, Voyage of the Little Mermaid, Toy Story Mania, and the Beauty and the Beast stage show. He may also enjoy Muppet Vision 3-D and the nighttime spectacular Fantasmic! Some young guests are afraid of 3-D movies in general, though this one is not a scary one. Also Fantasmic! has some spots that might be scary for a 2 year old, especially for a few seconds when it is very dark in the stadium. We bought our son a light up toy to have during Fantasmic! and that seemed to do the trick; he was never scared again.
You might also consider making advanced dining reservations at the Studios. If your son watches the Disney Channel, then you might be interested in
Playhouse Disney Play 'n Dine at Hollywood & Vine. Another good place with very young guests is the
Sci-Fi Dine-In Theater; don't worry about the movie clips -- they're much more funny than scary! In my opinion, the food isn't the greatest, but the atmosphere is outstanding. My kids love sitting in the cars while eating!
Have a good time in whatever park you pick!