SuperHero ABC by Bob McLeod
Just plain silly fun. Each page is filled with brightly colored detailed illustrations and chunks of humorous text. This is not necessarily for your little one just learning the alphabet though if they have issues engaging with simpler books it might do the trick. I think I need to get a copy for my friend who is a comic book geek. It might seem overwhelming in comparison to your average alphabet book but I think you need some variety and spice now and then.