Compare "The Raven" and "Annabel Lee" by Edgar "Allan Poe."

"The Raven" and "Annabel Lee" written by Edgar Allan Poe are very similar on many levels. Both poems share the heartbreak of a lost love. The use of imagery throughout the poem creates a mood that definitely differs between the two messages that Poe is trying to create. "Annabel Lee" has such an optimist view of possibly seeing his love again; while "The Raven" sets a tone far more daunting and sometimes down right scary. It is safe to say that although the poems have rhyming, repetitious styles and common themes, the defining factor in separating these two famous poems would be the overall tone.

"The Raven" and "Annabel Lee" are both poems by Edgar Allan Poe that address the desolation experienced by a man who has lost his love. 
In both of these poems, the speaker is experiencing profound depression over the death of a beloved--an experience that has resulted in sheer obsession and even, one might argue, madness. In the case of "Annabel Lee," this woman is the titular Annabel, a fair maiden who lives in a kingdom by the sea and is stolen away from the speaker when she dies and her body is taken away and shut up in a sepulcher by her "highborn kinsmen." In the case of "The Raven," this woman is the lovely--but also deceased--Lenore. 
Both speakers long to be reunited with their beloved. However, the speaker in "Annabel Lee" manages to find comfort in the idea that "neither the angels in Heaven above / Nor the demons down under the sea" could separate the two. In fact, the speaker manages to reunite himself with Annabel Lee through his dreams, claiming:

...all the night-tide, I lie down by the side
Of my darling--my darling--my life and my bride,
In her sepulcher there by the sea--
In her tomb by the sounding sea.

Meanwhile, the speaker in "The Raven" does not receive such satisfaction. When he asks the Raven, who he considers to be a prophet, whether he "shall clasp a sainted maiden whom the angels name Lenore" once he has died and gone to Heaven, the Raven simply replies, "Nevermore." He does not have the same luck as his counterpart from "Annabel Lee" and will not experience reunion with his lover. 
It's also worth noting that while these speakers face similar circumstances, the imagery surrounding those circumstances is wildly different. "Annabel Lee" is set against a bright and beautiful--almost fantasy-like--backdrop, while "The Raven" occupies more classically gothic territory--a dark and dreary night. While "Annabel Lee" benefits from the sweetness of nostalgia, "The Raven" has a more raw, immediate sense of suffering to it; these wounds seem more realistic and fresher for the speaker.
Additionally, while "Annabel Lee" takes on a singsong, almost nursery rhyme–like structure, "The Raven" is written mostly in trochaic octameter—a far more complicated and winding form.