Jack Skellington - The Nightmare Before Christmas(Disney)
  | Jack's
  childlike joy and determination make himbeloved by all who know him.He is a
  natural leader. However, he can be a bit naive at times, and is definitely
  not very good at reading other people's emotions - much to Sally's lament.
  Bored with his role of "Pumpkin King" on Halloween year after year,
  he becomes very excited when he learns about Christmas: a holiday very
  different from his own.  | 
Jack Jack Parr - The Incredibles (Disney)
  | The
  youngest of the "Incredible" kids,Jack Jack, at first, seems to be
  all sweetness and innocence, but no super-powers. But when the bad guy tries
  to take him away from the family that he loves, he shows everyone that he is
  the most incredible kid of them all. | 
Jack Frost - Rise of the Guardians (Dreamworks)
  | This
  smart, fun-loving spirit will be the first to challenge anyone in a
  competition. His sarcastic wit, though, doesn't hide the gentle and loving
  boy that he is at heart. |