People always discuss the intrincacies of transferring an artistic concept from one medium to another. When the concept gets elevated to cult status or makes a mark in one particular art form, it gets even harder. Which is not to say that it can't be done. The Hitchhiker's Guide to the Galaxy, for instance, exists in many incarnations, from the radio series to the books, to even an Infocom text adventure. The transition of comic books into cartoons seem to be natural, and usually successful.
The transition into movies, however, tends be much more complicated. In the worst case scenario, commercial interests turn what should be the adaptation of a work of art into a "spin-off," an exploitation of a "franchise." Of course, some may argue "it's just a comic book," so it's not like making a sculpture of Mona Lisa or a painting of The Thinker. But the character Batman is one of the most important archetypes produced in the 20th century, so the task of depicting it should not be taken lightly.
The previous attempts failed in different levels. In Tim Burton's case, from being excessively authoral: the 1989 movie, more than a Batman movie, is a Tim Burton movie; in my mental categorization it goes along with Sleepy Hollow, rather than with Batman: Year One. In Joel Schumacher's case, apart from being campy, his movies expanded greatly on what was Burton's major mistake: they focus on the villains. People tell the Batman movies apart by the villains: "the one with The Penguin," "the one with The Riddler." On the other hand, this is one of the aspects where Batman Begins excels: for once, we have a movie that actually focuses on Batman.
Batman Begins ignores all previous movies (the same way Burton's ignores the 1966 movie), and tells the story of the genesis of the character in its own way. The beauty of Christopher Nolan's concept is that, instead of requiring the viewer to simply enter into Batman's world, as we usually do in fantasy/sci-fi movies, in this one the world is built around you as the story flows. And this is fundamental, due to the properties of the different mediums. While in a comic book the notion of a traumatized man who suddenly becomes a masked avenger is almost natural, in a film this is much harder to achieve. We are seeing actual people on the screen, it is much closer to reality, and therefore it demands a more elaborate build-up for our suspension of disbelief. They went great lengths to achieve that -- including making some major changes to the story. While some die-hard fans will argue that they went too far, the concessions made construct a backstory that stands on its own and, most importantly, translates into a great movie.
In the comic books you don't question how a millionaire becomes a great fighter, but in a movie a guy doing some push-ups in one scene and then fighting criminals on the streets in the next just doesn't cut it. This Superman-like duality -- harmless in one moment, super-powerful in the next -- was a problem in the previous Batmans. The one portrayed by Christian Bale avoids this super-hero cliché. His Bruce Wayne and his Batman do feel like the same person, with the hint of roughness you'd expect from the part. Michael Caine's Alfred and Gary Oldman's Gordon are also very characteristic. In fact, one could say that while Batman Begins is not the most faithful one "factually," it may be the most faithful with regard to the personalities of the characters. Of course, there's always the issue of "which Batman" to take as a parameter, since comics with different target audiences tend to picture him with different intensities -- it's safe to assume, however, that the essential archetype is well understood. And it is definitely there in the film.
Christopher Nolan's approach of taking the Batman story and putting it into film instead of doing a "comic book adaptation" is in direct contrast with Robert Rodriguez and Frank Miller's Sin City. Fans of the Batman graphic novels like me -- especially of The Dark Knight Returns, by Frank Miller himself -- were usually less than pleased with the Batman movies. Many often wondered how would it be like if a movie simply took a graphic novel and transferred it to the big screen, with no stylistic changes. Sin City answers that question. Undeniably, the result is very interesting but, on what in hindsight may be somewhat obvious, it adds very little to the original. Batman Begins takes the exact opposite direction: it strips out the most pronounced stylistic elements and keeps just the essence of what makes the story what it is. By doing that, it produces a work that is tailored to that particular art form and, at the very least, gives the viewer a new perspective. In this movie, we actually see a series of events shaping the character of Bruce Wayne (beyond the simple "trauma with bats + parents killed") and how these affect his decisions and actions. Evidently, it is no Citizen Kane, but it has much more depth than the previous movies -- and, dare I say, than most movies currently out there.
I would still be curious to see a faithful movie rendition of The Dark Knight Returns, unlikely as it is -- if only to see the controversy that exposing that story to a wider audience would ensue -- but now I will no longer say that no Batman movie does justice to the character. Batman Begins does.