Well mankind seems to have always been drawn toward the "strange" and the "supernatural" and "things that go bump in the night". However if one can find a way to overcome the fear that tends to come with the "eerie" and things from the supposed "beyond" and rationalize it then you'll get a whole boatload of people following something even if it seems a bit bizarre.
However as a Christian I never really got into things like Dracula, Castlevania, The Mummy, Bleach, Buffy: The Vampire Slayer or Charmed.
The very FIRST time I picked up ANYTHING having to do with the subject of Vampires was after I learned that Twilight was written by a Christian author and had a spiritual message of "sexual abstinence," that it was a story of redemption explaining the power of true love over lust and was drawn from the book of Genesis account of Eve's encounter with the Serpent and the "Forbidden Fruit."
However I don't actually think that people should be so hard on Stephenie Meyer. I think that what she had done was needful and that it is a nice way of helping mainstream youth take a sincere look at "love", "abstinence", and "spirituality."
One reason that I think Twilight has become so successful is because the youth can actually relate to it. I think the reason that young girls and many women find solace in The Twilight Saga is because they suffer abuse from abusive boyfriends/husbands and find them as being a kind of "Vampire" in their life and hope to (like Bella Swan) bring the good out of them and help their troubled (like Edward Cullen) husbands/boyfriends overcome the "monster" inside of them and in the same process find true love as opposed to lust and at last gain redemption.
I myself, can relate to the whole thing after having gone through a nightmare of sorts with someone whom although I have separated myself from her I still love in my heart and hope to one day somehow find a way of giving her and myself redemption. I mean this very morning before the sun rose, at the time of the morning's dawn, right about twilight I found myself struggling to breathe as Desiree came into my mind. It's a haunting that might never leave me alone.
Besides the Twilight Saga like The Chronicles of Narnia is a positive alternative for Christians to the Harry Potter madness.
But of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die.
Genesis 2:17