I know there is a transformers animated tv show now, but I have never seen it. They have it on DVD at Target. Several years ago, there were the Teenage Mutant Ninja Turtles (called Hero Turtles outside the US) and the Power Rangers, and those are also geared to the young. But at their core, every major superhero has a "dark side" and most are the invention of some sad middle-aged man who feels the need to create an alter ego to help him have some sort of control over his life. I have seen The Incredibles and I thought it was awesome, but very dark for a typical 4y.o. (but only you know your child and how he might react). Maybe a fun activity would be to have your child invent his OWN superhero. You could really get some insight into what your child is thinking and what is important to him. You could help your boy create a new hero by drawing it or putting together a homemade costume. And he could make up the "backstory" and you could write it down, and then you'd have your own book to read and he could create new adventures from there. Just a thought. Enjoy this time while they are so creative!