Vampires in folklore were, predominantly, monsters. They were usually seen as somebody either living or dead, human-like, or barely resembling a human shape.
The uniting factor was feeding on the life energy of humans, though that could be just energy (there's a reason why we sometimes hear all the talks about energy vampirism), as well as blood.
Vampires were always a thing of the nightmare world and definitely the last thing anyone wanted to have to run into. It wasn't until the 19th century when the vampire was turned from a loathed monstrosity into a mystifyingly attractive object of desire.
Following this first short story - titled "The Vampyre" - came the one work of literature which is considered to be the cornerstone of vampires as we know them today - Bram Stoker's Dracula. From that point on, the fascination with vampire culture picked up and quickly gained momentum.
The vampire culture retains its popularity because of how romantically they are portrayed in many fictional works. One such example is Anne Rice's homoerotically-themed vampire series. Another well-known author is Anita Blake, and most recently – Stephenie Meyer and her "Twilight" saga.
Several movies have been made based on popular vampire fiction, and let's not forget the "Buffy the Vampire Slayer" TV series. From one writer to another, from one movie to another the depiction of these night creatures varies greatly.
Traditionally, the only way to kill a vampire was with a wooden stake through the heart, but the movie "Nosferatu" introduced a vampire being killed by sunlight, which later played a major role in most of the vampire movies.
Most interestingly, this culture has carried over into what we consider the real life - outside of books and movies. There are people who consider themselves being vampires. They have their own organizations and they practice the typical vampire lifestyle, generally meaning no harm to others.
No matter how you look at it, the vampire genre has become an undeniable influence on more than just literature and motion pictures. Making the subject of Vampires in folklore an ever growing area, filled with tales of evil, lust and even sometimes love.
" Her blood coursed through my veins sweeter than life itself." -- Louis, Interview with A Vampire