Nice collection, BaB. Out of the vehicles you've posted (excluding the Batman Begins), my favorites are the first and third ones. Do you have figurines as well? I know you have the 1st and 2nd DVD seasons.
My suggestions on what to add to your collection:
• movie posters
• trading cards
• hat featuring logo + other clothing
• Batman suit + other movie paraphernalia
• official soundtracks (if they exist)
I have two giant binders full of Batman trading cards from the original movies. Good luck with your obsession.
