Now I come to think about it, having re-shelved his novel, the most memorable aspect of Stoker's writing in Dracula for this reader was the amount of non-standard dialect he attempts to render. This begins with the thick Yorkshire dialect of an old man in Whitby, but we get something similar from lower-class characters in London as well. It's intensely patronising in its way, but also seems to reflect a genuine enjoyment of the vigour of their language. It struck me as theatrical, as though Stoker is thinking of these characters entertaining us on stage, and I couldn't help but think of Stoker's own experience of the theatre in relation to this.
In fact, there's something very theatrical about much of the novel and this explains, I think, one of its obvious technical flaws. The various personal narratives that make up the text in something close to epistolary fashion work well in terms of providing different perspectives on the action but never convince for one moment in terms of suggesting genuinely differentiated voices, and the idea that the writers somehow manage to capture verbatim the extended speeches of other characters, like the old chap in Whitby, is risible. But if we read the novel as something close to a theatrical script with the speeches as enjoyable set pieces then there's a kind of logic to which we are prepared to surrender just to enter the world of the novel.
The extended speech of the maniac Renfield, when he attempts to convince the others of his regained sanity, is the best example of this. It manages to be sinister, pathetic and funny all at the same time, and it's easy to imagine a fine actor (like Irving, whom Stoker served as dresser) making this work wonderfully on stage. Similarly, imagining Van Helsing as a theatrical performance rather than a character makes him a good deal easier to put up with.
I wonder if this the fundamental reason that Dracula has served so well as an ur-text for so much vampire fiction. Film-makers particularly seem to have drawn from all that is stage-worthy in the novel, but the dark power of the Un-Dead is just a thrilling add-on, not central to the work in any sincerely disturbing manner. It's all surface, highly entertaining in its way, but nothing to keep one awake or colour one's dreams.