In this case, I chose an interesting image of Christian Bale as The Dark Knight. It is important to pick an image that has enough contrast to allow for good light/shadow interplay. For Batman, the light playing off his armor provides some excellent (but challenging) details that I thought would show up amazingly well on my pumpkin. His strong stance and look in general also makes for a great presence when lit.
Image credit: Google search, DC comics, Warner Bros.