So much of what we consider "typical" vampire traits were invented by Hollywood, not the old myths. For instance, vampires burning in the sunlight was first seen in the film Nosferatu because the director thought it was beautiful and poetic. In Bram Stoker's original novel, Dracula was free to move about in the sunlight. He just didn't have access to all his abilities, and thus was stronger and more frightening at night. Old folklore says nothing about sunlight, either.
Personally, I'm fascinated by the commonalities within certain myths. And I like the obscure ones better than the ones Hollywood has invented. In some traditions, they can't cross flowing water, or they have to count every grain of sand thrown at them. Religious artifacts may or may not work against them. The vampire myth predates Christianity, and it should be noted that crucifixes working against them came into the folklore with the spread of religion.
The two defining traits of the vampire are a hunger for blood and rising from the dead. Both of these seem to be prerequisites in any myth. It's the thirst for blood we seem to find most compelling, as its taboo and often used as a sexual metaphor (thank you, Mr. Stoker). Originally vampires were ugly and often less intelligent than people, sometimes having no memory of being human at all. But thanks to Bela Lugosi, we now think of vampires as being extremely attractive. And as the fear of foreign men preying on our innocent young girls dissipated, vampire became more sexually ambiguous to portray fears of homosexuality and rape. Again, this is something Hollywood and pop culture have invented.
The pop view of the vampire differs wildly from the vampires of folklore. People have been playing with the myth for a long time, inventing and dropping aspects as they see fit. I think the key problem with the Twilight vampires isn't in their creation, but in their creator. A more talented writer might have been able to pull of the sparkling thing (I say maybe here, not definitely), but Meyer just doesn't have the skill to make it seem anything more than trite. What bothered me about the books (especially after my sister, 8 years older than me and normally of sound taste, recommended them heartily), is the lack of characterization. It's standard romance fare, but with the pretense of being a vampire novel. If I wanted to read trashy vampire novels, I'd read Anita Blake. ba-dum-tish
