The one that immediately punches into my head is 'The Raven.' It's not just the plot, which is basically a guy going mad over a talking bird, but the entire package Poe engineered. The hypnotic, repetitive rhythm of 'Nevermore,' the escalating despair in that gloomy chamber, the way the meter feels like a heartbeat slowing down—it's a masterclass in using sound to create dread. It became iconic because it's so perfectly self-contained and reproducible; you can feel the atmosphere in just a few stanzas. That poem distilled his whole aesthetic into one unforgettable package.
Honestly though, part of its fame is almost pop-cultural. It's short, quotable, and has that instantly recognizable, almost musical quality that makes it easy to parody or reference. The imagery is stark and simple—the bust of Pallas, the velvet violet lining—yet it builds a whole world. It cemented the trope of the tortured, bereaved intellectual and made melancholy stylish in a way that still resonates. For a lot of people, it's their first and only exposure to Poe, and it’s a powerful enough dose to stick forever.