Daybreakers is an Australian-made vampire film that explores some traditional vampire tropes in unconventional ways by taking them to their logical limits. Set in the near future, it has science fiction and horror elements skillfully mixed. Except for Willem Dafoe, I did not recognize the cast.
The premise is ecological. In a predator prey-relationship, if the population of predators goes above the level that the prey population can support, it will crash. Not enough antelope = starving lions. The mathematics (called Lotka-Volterra dynamics) are very beautiful.
Many vampire stories assume that vampires will carefully cultivate the human population they feed on. Not Daybreakers. This movie introduces a destabilizing idea - that vampires will 'promote' many humans instead of feeding on them, for essentially loving reasons. Done with the best intentions, but in the future of Daybreakers, ten years after a vampire plague of unspoken origin, most of humanity are now the immortal undead, kings and queens of the night.
For the sake of argument, if a vampire needs 60 humans as a stable blood farm to provide a renewable resource of one pint a day, you can see how converting 90 percent of the humans to vampires is going to lead to 'instabilities'. There is just not enough blood to go around. Blood is both food and currency in this future.
The premise is inventive. The details are worked out nicely. The film is a good blend of horror and s-f. Those who are fans of traditional effects, as opposed to CGI, will be happy. My main quibble is that it solves the main problem twice, apparently for cinematic rather than in-story reasons. I enjoyed the music quite a bit.