@hue-man,
Auteur theory goes a long way here. Other arts usually have a singular artistic vision: visual arts, literature and music. Collaborative and complementary artistic visions exist in these and in theatre. In the latter case, the writer imposes a particular vision in some fields, the director in others.
A lot of films aren't expressions of anything. They are a consumer item made by a corporation. Others have rather modest expressions, usually from film-makers who know their craft but work within the studio system. But some people are so successful within that system, or by working outside of it, that they can impose a dominant artistic expression. The most dominant expression comes from the director, or better the writer-director. Such artists have always existed, from Murnau, Chaplin and Pabst via Ophuls, Hitchcock and Godard to, today, film-makers like Bela Tarr, Abbas Kiarostami and Pedro Almodovar. These film-makers are true artists, whether they make us laugh (like Chaplin), cry (like Ophuls), scared (like Murnau and Hitchcock) or think (like Godard).
I do think auteur theory does underplay the roles of other artists, such as the cinematographer (where would Godard be without Coutard) and the actors (Chaplin's performances made him probably the finest cinema artist there will ever be). Film is still a collaborative art, and one could imagine that the number of collaborators does not necessarily diminish the work.
So, to me, film is art when it is made by an artist. I believe this about all art forms: a lot of pop fiction and music are simply commodities to be manufactured and sold. It may seem a snobbish view, but when I watch Last Year in Marienbad, I
feel I'm watching art. When I watch Die Hard 4.0, I feel I'm watching money being made
Action films are an interesting genre insofar as it seems like a no-go area for film artists. Many great artists have tackled comedy, horror, sci-fi, war movies, sports movies, period movies and even erotica (Kubrick tackled all of the above), but action is avoided. The most artistic director I can think of who has tackled the genre is Spielberg. Spielberg is the artist-as-storyteller, a field I'm not sure is actually art but craft. But this also explains why action films are usually of such bad quality in most respects. The Bourne films have attempted to redress this balance, but they are still purely visceral: they provoke a short burst of adrenaline and then... nothing. Surely art should remain with you.