My absolute favorites are mostly your standard entries that you’ll find on plenty of top 10 lists:

• Halloween
• Alien
• Scream
• Night of The Living Dead
• An American Werewolf in London

Apart from these, I’d recommend

• The Wailing (2016, 156 minutes): a Korean movie about a detective trying to find the cause of a mysterious disease running through a town
• Barbarian (2022, 103 minutes): this movie falls in the very weird “AirB&B” sub genre of horror. It has some scenes of incredible tension, one of the best (and well-earned) jump scares, and some great humor.
• The Return of the Living Dead (1985, 91 minutes): a horror-comedy zombie movie with some incredible practical effects

For my least favorites, I’d probably put Slenderman, Meghan is Missing, Winchester, and Ghosts of War.

favorite: hereditary. maybe a cliche answer but it’s genuinely the best horror movie i’ve seen in a long damn time, everything else is so generic and follows the exact same predictable formula. hereditary didn’t do that at all.

cant say i have a particular least favorite, because almost all of them are bad and forgettable, therefore I forget them lmao. a bad but good horror movie i love is the later chucky movies like the bride or chucky and the seed of chucky, which are more comedy horror and bad in a good way

A few have mentioned Hereditary already so I’ll give an honorable mention to Dark Skies with Keri Russel.

Hard to pick a favorite. If I had to pick a personal favorite I’d say In The Mouth of Madness. I’ve never seen it brought up as often as The Thing or other Carpenter films, but it was the first “meta” horror movie I ever watched and I’ve always had a soft spot for it. Besides that, there are a few I make sure to watch every year. I have to watch Trick 'R Treat sometime in October and I usually start December off with Krampus (2015). Also, I’m not sure it even qualifies as horror, but One Cut of the Dead is a great one for horror fans or just movie fans in general, especially if you like lower-budget films and the passion that goes into making them. Admittedly the first twenty minutes or so can be hard to get through on the first viewing, but it’s a great movie if you stick with it.

Least favorite I’d have to say, Lake Mungo. I don’t think it’s a bad film. I just went into expecting found footage horror and got a mockumentary about dealing with loss and uncovering a deceased family member’s secrets. Again, not a bad film but not what I was in the mood for when I watched it.

Up front warning: This is the ultimate low budget b movie campy horror film. It was written and shot in a seven days on the sets of another movie. It is not scary and is by no objective means a good movie. If you like campy low budget slashers it’s a must watch.

Sorority House Massacre 2. Five college women spend the night in their new sorority house, the old Hokstedter place, and make the mistake of using a Ouija board. It has a great twist revealing an unlikely hero and the last line of the movie is my favorite line in all of cinema.

Least favorite: Sorority House Massacre. Maybe the worst example of a low budget slasher flick ever made. This movie is so bad that the sequel used clips from a different movie, Slumber Party Massacre, for it’s flashbacks and backstory. While intended to be scary campy low budget slashers flicks tend to be so ridiculously badly written and acted that they become parodies of themselves and present as humorous movies. Sorority House Massacre isn’t interesting enough to reach this important self parody status and winds up being neither scary nor funny.

I’m a big fan of the found footage (FF) subgenre of horror. Some favorites would be Gonjiam Haunted Asylum (2018), Cloverfield (2012), and Hell House LLC (2015)

Classics from my childhood:

The Exorcist
Exorcist III
The Fly
Evil Dead
Poltergeist
The Thing
Prince of Darkness
Hellraiser
Carrie
Jacob’s Ladder
Pi

Modern:

Hereditary
Nope
The Night House
Annihilation
A Quiet Place

Best meta horror:

Tremors
Malignant
Cabin in the Woods
Death Becomes Her

Favorite is house of 1000 corpses.

Favorite: The Thing, the John Carpenter one from the 80s. It is perfect.

Least favorite: Nightmare on Elm Street. I like other Craven stuff but could never get into this one.

John Carpenter’s The Thing is not just my favorite horror movie but it’s on my list of top 5 favorite movies of all time. I just love that movie to bits on so many levels. Other favorites of mine include Alien, Evil Dead 2, Creepshow, and Return of the Living Dead. Though some honorable mentions to The VVitch, Barbarian, and The Lighthouse (does The Lighthouse count as a horror? Eh. Whatever. I do really like it).

Sinister. There’s something about the home videos that just gets to me. Wish the second one was as good as the first!