Though film is a collaborative process, there are still a number of creative individuals who rise to the top in importance. The director obviously being a big one, with the screenwriter, producer, and other such individuals like cinematographer and composter who fill out the rest. And then of course there's the actors themselves - more than even the director, this one is the most obvious, to probably even anyone who doesn't know much about the craft. We tend to give actors (perhaps at times undue) credit for their relevance to a film - particularly given the nature of celebrity. But at the same time, there are plenty of examples that demonstrate that the right actor in the right role really can make or break a film.