The titular dragon in THE HOBBIT: THE DESOLATION OF SMAUG has been one of the great movie monsters waiting to happen for more than 70 years. The creature is pretty much the great dragon of modern literature and manages to define and nearly overshadow the book he was created for, even though he only actually appears for two chapters of it.
And the dragon is absolutely one of the best things about the film. That's the good news.
The bad news? Smaug really deserved a better movie.