Dracula by Bram Stoker is one of my most favorite classic horror novels. Published in 1897, it introduces the character of Dracula, patterned after the real life villain, Vlad the Impaler. While the novel uses the language of the time which takes a little bit of getting used to, (for example, the word "whilst" is used, instead of the word "while") it is a great read. I really enjoy the book, because being one of the first truly classical horror novels, it relied on story and suspense and plot rather than messy gore or body count to impress its audience.
Stoker's Dracula has inspired numerous movies based on his original idea, my favorite of which is the black and white 1931 classic Dracula, with Bella Lugosi as the title character. It barely follows the plot of the book, but that's really okay. It has its own plot, which works for the medium in which it is. It keeps the feel of the book, I think, and the actors played their parts well.
I would recommend the book Dracula to anyone, as well as the 1931 movie. I enjoyed them both, and will continue to enjoy them in the future.