If you're looking for inspiration for your Dark Heresy RPG campaign, or other sci-fi game which features an apocalyptic dystopian future, check out the movie Priest, which came out in 2011, directed by Scott Stewart. It's a good flick, featuring an eternal struggle between a priesthood and vampires over a shattered world.
And the main character drives an awesome motorcycle while he searches for his kiddnapped nice before she gets changed into a vampire.
The movie soundtrack, composed by Christopher Young, lends to the tone of sad stoicism throughout the movie. There are a couple of tracks decent for action sequences for your game. "A World Without End" is great example of what to expect, being sort of a montage of the other eleven or so songs on the album.