This is the best of Poe's short stories I think, and it comes a close second place to "The Raven" for the best thing he's ever written. The murky, unhealthy House of Usher, inhabited as it is by the sickly remnants of a great family, is deeply disturbing. The imagery, here, too, is very strong - particularly that related to the tarn which eventually swallows the house. I do feel it's slightly over-written in places (Poe's prose does have a tendency both to the purple and the over-explanatory), and I'm never quite convinced as to whether Roderick Usher is a well-drawn character or not, but the whole creepy thing is still immensely entertaining.