Don’t think, just the top 5, right off the top of your head. Let’s allow two honorable mentions. Which versions is not important just names.
Psycho
Alien
Horror of Dracula
Hellraiser
Hostel
Assuming the influence is on horror movies that followed …
Frankenstein
The Thing From Another World
Psycho
Night of the Living Dead
Blair Witch Project
Honorable mentions:
The Uninvited
Invasion of the Body Snatchers
Shining
Suspiria
Night of the Living Dead
28 Days Later
Under the Skin (Too soon to say if influential, but it influenced me!)
Zombie (original name Zombi 2)
Dawn of the Dead (1978)
Shutter (2004)
The Last House on the Left (1972)
Deranged (1974)
Talking about influential, versions matter…
For me it’s
Arachnophobia - I am scared of spiders, especially large ones ever since watching that film. If I see those huntsman spider I’m going to use a flamethrower.
Alien/Aliens/Alien3
Tales from the Crypt series (not a film, but still)
Scream/Scream 2/Scream 3
Friday the 13th
The times they came out were pretty important.
Texas chainsaw massacre was pretty twisted.
Alien was certainly right up there
If you grew up in asia anything japanese ir thai was right scary! But bad acting so in line with western horror budgets.
Cliche, but blair witch project with the first month had its real feel moment.
The cube. Disturbing. $39nt buy from carrefoure clearout bin.
Hostel was grose not scary. Like saw, and so many others. But scary for first time backpackers travelling alone im sure!
The Blair witch project
Evil dead
Night of the living dead
The exorcist
Nightmare on elm Street
Honorable mention: Alien
I focused on influence, not necessarily on quality.
In terms of influence Nosferatu has to be number one, no?
Any Celine Dion concert film.
So scary, I haven’t even watched one yet.
It is the modern age. Most influencial now means what most influenced ME haha. None of us are over 100…but ya a good flick for the time no doubt. How did it influence people then? Interested to hear.
Thinking more about influence…perhapss fantasia is reaponsible for a few dellusional shoot outs.
I think so, but frankly the Stoker estate’s lawsuit against the producers resulted in the physical destruction of the film (Murnau’s family managed to hold onto at least one copy). It was largely unknown until CT Dreyer’s Vampyr: The Dream Of Alan Gray was made and released in 1932.
It seems that Stoker’s heirs managed to quelch the Murnau production enough to prevent its entry on this list, although it’s a terrific and instinctive horror film - but one that we only learned the existence of in the 1950s or so. Top shelf Murnau, although it was seen widely long after it could have possibly been influential.
eta: Seems the Murnau family was able to send copies to America before the 1950s. Still, that could make Universal’s Dracula more influential than Nosferatu on later horror movies.
But when was the last time anyone watched a horror film and thought oh yeah they totally copied this from Nosferatu (or from something that got it from there)? 
I have in fact seen the Celine Dion singing AC/DC performance online, and have never been the same since. Scarred for life. Some horror movies aren’t worth watching. Save yourselves.
How old are you? 
Why? Is the Klan movie a great influence because it was first?
I don’t know much about movies, but that was my thinking. Usually the first in a genre is influential. There was a horror movie, of sorts, before it called The Cabinet of Doctor Cagliari.
Anyway, nobody agrees with me so I’ll assume my theory is wrong.
Well, I don’t think Nosferatu is not influential…but I push back against the idea that it is significant in the modern era…not that you specifically did.
You obviously haven’t seen The Innocents (1961). Definitely one of the best horror films of all time.
You mean the KKK? 