Over at LifeTeen's blog, Christina Mead listed five reasons why she's not seeing Twilight: Breaking Dawn 2. I agree with most of her points, though I want to take number four a little further. She says that "Vampires are weird", and she's right. Yes, vampires are weird, but modern vampires are differently-weird.
Early vampires were weird. Unnatural. Demonic. They were set apart in just the opposite way that Christians are set-apart. They take life from the blood of others, while Christians receive life from the blood of Christ. They live in darkness and shun the light, while Christians are called to walk in the light and turn away from darkness.
Early vampire stories pit good against evil. Modern vampire stories pit good-evil and really-evil-evil - a relativistic showdown. These monsters here are okay; those monsters are bad. They teach us that a certain amount of evil is okay - as long as its the right kind.
And for Bella, Edward is the right kind of evil. He's not so bad. In the end, she dies for him, not to save him but to join him - to become inhuman.
In the end, her reckless and, at times, destructive behavior pays off. Teen angst and attempted suicide work. She gets her "man".
What lessons does Twilight have to teach us? Put your life in danger for a boy. Lay in bed together, as long as you try your really very best not to do anything. Give up even your humanity, your soul, to get what feels good right now. The series is appropriately named, as we see in this, perhaps, a twilight of the traditional vampire story, and the lessons in morality and faith that accompanied it.