When I first went to the Animal Kingdom I didn't hear good things about it so I was a little guarded. I kept hearing that you won't see many animals so it was a waste of time and money.
Boy was I surprised to see almost *every* animal they had! The gorilla was putting on a real show that day -- pulling apart newspapers and just all around being entertaining. The only one that wasn't available to see was in with the vet that day. I don't remember which animal it was but it was the one that I really wanted to see because I'd never seen one before. Go fig, eh?
If you want to get a truly safari-type experience, stay at the Animal Kingdom Lodge and ask for a room that faces the park. My sister and her family stayed there last year and woke up to a view of elephants (I think elephants). Now where can you experience something like that without paying an arm and a leg?