Poe and the Unreliable Narrator

Many of Poe's stories touch on the supernatural, but it is often unclear whether something unusual is happening or if the narrator's psycoses are in play. 

For example, "The Tell-Tale Heart" features a narrator who has decided to murder a man whose appearance bothers him, but who has never actually harmed or offended the marrator in any way. When the beating sound begins, we are not told whether it is actually audible to others, or if we are being reported something real only in the narrator's mind. 

"The Raven" is similar. The poem's narrator is overcome by anguish over the loss of Lenore, and may not be completely well of mind. When the raven steps into his room and repeats, "nevermore", the reader must wonder whether this is a real occurence or the creation of a lonely man desperate for company. 

I really enjoy Poe's creation of a not only partial but also possibly unreliable narrator. The first-person narration puts us inside the story, and may be giving a totally different account than what is "really" going on. I suppose, though, since the story itself is fictional, the account of what "really" happened is rather insignificant, in a funny meta sort of way.