The thing that films and comics have in common is entertainment. They're both meant to be inexpensive ways to keep an audience entertained with their stories & visuals (or art). With films people expect to see something well rounded. Let's face it, it's all that they're getting for three, four or even 8 years. Unlike the comics, you're not going to get a new issue, erm, film, every month.
There are a number of comics that could be adapted. Batman Year One is a perfect example. It has the right tone for a live action film. But they would have to focus more on Batman/Bruce Wayne, add more action (less drama), expand the story and make Catwoman's presence relevant. It could stay very true to the graphic novel however it would be more of an expanded version of the story.