[comic-book guy alert]  
A concise, 60-plus-year retrospective of Bat-Art. Via Waxy.
Here's a quick fun fact.
SuperNintendoChalmer: Originally, the emblem on his chest was just a silhouette of a bat. DC added the yellow oval around it when they were told they could trademark any bat shape.
Hugh2d2: All Batman links get a 10 from me!  
geesh this brings out the comic nerd in me
Psychomike: here's a ten and a comment