It's a dreary October day and you have nothing to do.

Halloween
Friday the 13th Part 2
A Nightmare on Elm Street
Childs Play 2
Candyman
Scream

Ghost Ship
The Ninth Gate
World War Z
Wicker Man (Cage)
House on Haunted Hill 1999
The Haunting

I'd go on a Lugosi/Karloff kick:

Dracula 1931
The Mummy 1932
The Old Dark House 1932
The Ghoul 1933
The Black Cat 1934
Isle of the Dead 1945

Alternative theme - slasher

Halloween (part 1)
Friday the 13th (part 1)
He Knows You're Alone
The Burning
The Prowler
Dark Night of the Scarecrow

Halloween ('78)
Halloween II ('81)
The Texas Chainsaw Massacre ('74)
The Exorcist
Se7en
Friday the 13th Part 3

Sorry for only posting the Poe poem and not contributing anything of substance there, but I can’t really better others’ choices. Just so you know, my own tastes lean toward the classics, and (or “so”) I’m not one for slashers.

Anyway, a few that haven’t yet been recommended:

The Uninvited (’44), actually set in May but spooky and autumnal in mood—I first saw this one as a kid, by way of a terrible, scratched-up print, and on a dark and stormy night to boot. The best possible first-watching! Love it though I do, it’s never quite held me in the same way that it did that first time, probably because of the mood that night. Bosley Crowther put it perfectly: it’s like “…a ghost-story weirdly told to a group of shivering youngsters around a campfire on a dark and windy night.”

House on Haunted Hill (’59—I see the remake is listed above, but I’ve never seen it), an overblown and absurdly hammy movie that, exactly because of these qualities, is great fun. Years ago, a pal and I watched it right before Hallowe’en and had our own MST3K-esque commentary going on, but we loved it. Price is a hoot.

I first saw Drácula, the Spanish-language version of the ’31 Lugosi film, on a dark and stormy night at Hallowe’en time as well (I’ve seen a lot of spooky movies that way, for whatever reason—not that it’s spooky, but I always associate Murder on a Honeymoon, in the Miss Withers series, with Hallowe’en because it was on TCM a few years back right before I went to a haunted house). I’m not as fond of it as the English-language version, which vegalyra mentioned above, but it’s a good one for Hallowe’en viewing.

I keep on recommending the movie Three Cases of Murder (’55), but I’m pretty much only recommending the first segment, “Into the Picture.” It’s a small masterpiece in an otherwise mediocre anthology-movie.

One more choice, which may seem unusual but in fact has a lot in common with old dark house spooky stories: Cocteau’s masterly La belle et la bête. A fantastic, beautiful, evocative, and in fact rather spooky film, in the spirit of the old fairy tales. Wonderful in the truest sense of the word.