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.

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).

My favorite is John Carpenter's The Thing, with was already mentioned here by @Ragnell

My least favorite would be Bird Box (is that a horror film, or just a thriller?). I tried watching it and was just bored the whole time. If Bird Box doesn't count as horror, then I'd have to say Cronenberg's The Fly. It's not a bad movie per say, but it just didn't work for me for whatever reason.

Some that immediately pop into my head:

Krampus. It's mildly scary but the audio and atmosphere is phenomenal.

Trailer Park of Terror. Just sit back, drink a couple of beers, and enjoy this B-rated movie in all it's glory.

Slither. Horror comedy that's great for people who don't like a ton of scary but don't mind blood and gore.

Tucker and Dale versus evil. A comedy with a unique perspective to the horror genre. A must watch!

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

My favorite will always be The Shining, which I have seen so many times. I first watched it when I was far too young and now it's part of my personal schema.

Least favorite, Turistas, which gave me a near panic attack from second hand claustrophobia. Never again.

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

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.

How would you like to feel extremely uneasy and uncomfortable?

Try Skinamarink

This is absolutely an either you love it or hate it film. I can 100% understand why people hate this movie - every single shot in this movie is out of focus and not directly showing you what is happening in the scene. It requires 100% focus to decipher (or come close to) what's going on. It made me feel like a kid in the dark, which is what this movie is about - a brother and sister stuck in their home in a forever night as some entity begins to hunt them.

Content Warning - Child Disfigurement.

If you're looking for a popcorn horror movie to watch with a loved one, skip it. If you're interested in something truly, truly experimental, give it a shot.

Sleep Paralysis: The Movie

Favorite is house of 1000 corpses.

Least favourite: Event Horizon
I like sci-fi, not ghost story in space.

Favourite: A Quiet Place
Excellent pacing, truly terrifying threats.

Juon. Not the American remake The Grudge, the Japanese version.

In the Japanese version, the house felt like a normal, everyday house, and that’s what made everything scarier. It was lit like a normal house, unlike the American version.

Also, that scene were Toshio, the ghost child, is on every floor as the elevator went up literally had me backing up trying to get away, it creeped me out that much. Juon had so much subtle horror like that, along with the big scares.

And as for least favorite, I guess the Saw movies. I never much liked the torture porn genre. I prefer being creeped out than grossed out.

Event Horizon, the babadook, the first couple of Cube movies and the Child's Play series are my faves, with Bride of Chucky being my all time fav.

Other faves include American Mary, Terrifier, Cabin in the Woods, Dead snow, and happy death day. If I'm feeling like I want something dumb I'll go after some Full Moon movies, the evil bong and gingerdead man (first one) are great

I really like the old Dario Argento movies. They're artsy and gross in equal measures. (And you just know that guy really wants to strangle someone.)

Suspiria tops the list. I also liked the sequel, Inferno, which is probably underrated. The underwater apartment rooms were really disturbing.

I wasn't a big fan of the 2018 remake.

REC (Spanish) is probably the most successful horror that actually has me on edge most of the film.

Martyr is one that I seldom see mentioned. If you like a slow burn, psychological horror movie, check it out!

The Ghost and the Darkness.

I’ve seen it once. I was… 6 years old? Somewhere around there.

Gave me nightmares for several years. There’s only one other movie that’s ever had that effect on me.

And in terms of night terrors, I actually far prefer dreams about getting pulled out of a canvas tent into the night and getting devoured by a lion to some alternatives. You can fight back and stuff, it’s way better than those dreams about burning alive.

So, long story short, if you lucid dream hard enough you can kick a nightmare’s ass. I’d really rather not though, it’s a lot of work, so in that sense I sincerely hope the Ghost and the Darkness is the best horror movie I ever see

I'm a horror geek, so my list is biased toward my interests, not what is "best".

Favorites:

1. Halloween (1978)
2. Hellraiser II: Hellbound
3. The Shining
4. Event Horizon
5. The Lost Boys (this one is only vaguely horror, admittedly)

Bonus: Nightmare on Elm Street because it's the only one that scared me as a kid. Freddy really came into my dreams so I thought he was real for a long time.

Least Favorite (no particular order):

-Paranormal Activity
-The Purge
-Killer Klowns From Outer Space
-Child's Play

Favourite is tough, because there are horror films that I think are the best in show (barbarian, vvitch, the shining if it counts as horror) but the ones I like the most are campy. So maybe evil dead 2? Is that cliche?

The worst I’ve watched is also not based in subjectivity but saw IV is when I realised that horror was a commodity and tickets were being sold based on litres of blood you can see being spilt. Fwiw I enjoy the first three saw films

Favourites (in no particular order):
The thing
The VVitch
Under the shadow
the shrine
Kairo (Pulse)
The Autopsy of Jane Doe

Disliked:
It Follows - i liked the concept...didn't really enjoy the second half of the movie though
Lake Mungo - i had to watch it 3 times because i kept falling asleep during it

I got sucked into binging the V/H/S series a while ago and enjoyed all except Viral, which I turned off midway through as it was boring me to misery. 94 and the more recent 99 were the standouts for me.

While not really a fan of horror movies, there are plenty that I have loved, as films in the general sense and not specifically as any genre.
At the top of the list for me, it has to be the original The Wicker Man, and in second place it's Evil Dead Pt 2.

As least favorite, not one specific film but the entire slasher film realm.

Manos The Hands of Fate for all categories (the MST3K version obviously)

28 Days Later

Favourite good horror: The Fly (Cronenberg remake), The Thing

Favourite bad horror: Manos: Hands of Fate

Least favourite horror : something called Fear.com

I’m going to take this as an opportunity to promote House (1977). I can not begin to properly articulate how much I love this movie.

As for one I’m not so fond of, I’d have to go with The House of Seven Corpses (1973). It was just super mediocre and barely memorable at all.

After developing PTSD for an unrelated issue, I can’t watch horror anymore. But before that I was a fan. I remember being distinctly disappointed by the Silent Hill movie as betraying the core fundamentals of horror writing, and frustrated that they took what was supposed to be a psychological journey into the psyche of the main characters and turned it into a boring “evil cult” story. They didn’t even make the cult scary in the way real cults are scary.

A friend of mine actually liked the movie, on the premise that it wasn’t trying to be horror, but just a shock-value gore-o-rama. I don’t see the appeal.

The scariest movie I ever saw? Literally gave me nightmares and kept me up for weeks? The Exorcist. It probably helps that I’m kinda religious. Regardless, never watched that movie twice. Even if I didn’t have unrelated issues, I’d never watch that movie again. A+ horror.

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)

Fav right now is probably It That Follows. I really like a lot of the set choices and the concept itself.

But for all the people looking for a movie they haven't heard of try Pontypool. It's an odd take on an infection movie. It won't top your list but you'll see some different things.

We all either love horror films, or hate horror films.

Ehh I don't like torture porn or movies with stupid loud noise jump scares, but I love anything horror that's camp or schlock, like

Chopping Mall
Evil Dead 2/Army of Darkness
Fright Night (1985)
The Hazing
Night of the Comet
Reanimator
Return of the Living Dead

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.

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