I have not yet read a better vampire story than Tim Powers' 'The Stress of Her Regard', and I doubt I ever will. It ties vampires into the lives of the Romantic poets in a seamless fashion and doesn't have a single wasted detail. It also has the most innovative take on just what vampires are that I've seen in a novel.
That said, I'm also currently enjoying 'Dracula Unredacted', by Ken Hite and Gareth Ryder-Hanrahan, because it's pure geeky fun. The authors have re-imagined Stoker's novel as an after-action report written after the botched attempt to recruit Dracula by British naval intelligence in 1894. Not only that, but they've added in margin notes from subsequent generations of MI6, tying Dracula to a coup in Romania in 1940, a mole-hunt in London in 1977 and present-day operations against Al-Qaeda.
Like I said: pure geeky fun.