Vampires survive in our mythology precisely because they are creatures of fantasy, which allows them to keep up with the times. As our list of fears grows and changes, so too do they.
That's why the vampire works its magic so deftly. It's the sum of our fantasies and fears, and so long as we fantasize, so long as we fear, it will still be with us. If our beliefs change over time, it will change to match us. It's the perfect psychological horror icon.
Psychological horror is a mental medium. Its impact depends as much on what you don't see as what you do.
Every time horror is dragged into the daylight, it loses some of its mystery, and with it, potency. The realization of a fantasy, however it is done, is always less interesting than the anticipation, precisely because the anticipation relies on feelings, impressions, and sensations that even when felt most strongly cannot be put into words, nevermind into pictures.
Dracula is a classic example of the need for less, not more. The Count himself is absent for most of the book. He establishes himself in the opening chapters, but after that, his appearances are fleeting. The reader can't even be sure whether Dracula was there at all; perhaps that bat was just a bat, or maybe that poor old man in Whitby churchyard died of natural causes. Maybe, maybe not.
So, best vampire in gaming? The electronic inheritor of the empty coffin is none other than . . .
The G-Man from Half-Life.
Now, before you start, remember: the fangs, the garlic and the rest? Most of that is silver screen mythology. The folklore behind the legend is much stranger; give Montague Summers a look, if you don't believe me. The key points to take away are: looks human, but isn't; eternal life; abilities far outside human experience; revels in suffering and often causes many deaths. The outside evil who destroys without remorse.