I'm actually reading Dracula right now. I picked up a cheap copy of it about a month ago as research material (I'm a writer, I was interested in novels written in the form of personal letters). And yes, it's very good, assuming you enjoy late 19th century popular literature (and generally speaking, I do). Movies are never exactly like the books...pick up any of the old Ian Fleming James Bond novels, and prepare for a shock...the movies have nothing in common, save for the titles and maybe a few names. The same can be said for Sherlock Holmes. Most people think of him as being this sort of passive, effete detective who crawls on the ground with a magnifying glass while his fat little buddy sits around and acts amazed at everything he does. Actually, Holmes is kind of a manic-depressive guy...in the books, he tends to fall into these spells of lethargy where he just sits around, injecting himself with cocaine and not moving much, until a case drops into his lap. Watson, while extremely impressed with Holmes, isn't a slack-jawed idiot. And he's not all that fat, either. He starts out in the books emaciated and sickly looking, because he was getting over dysentery from his time in the army in Afghanistan. When Holmes remarks about his weight (several stories later), he's pointing out that Watson actually looks to be at a healthy weight now (he'd been recently married, and his wife was feeding him).
It's unrealistic to expect movies to follow a book that closely. Though I can understand people who get upset at some of the changes made when a book goes to film. I'm still a little bummed out about how Gimli was portrayed in the Lord of the Rings films...he's actually an interesting, cool character in the books, and in the film he's just a stereotypical beer loving dwarf.