It's a tossup between the first and second.
I kinda prefer the second because the ending of the first one, as memorable as it is, sets off a lot of questions on how an older woman could possibly have done all things she did.
In II, we have Jason and thankfully without the hockey mask.
I am not a fan of the series. I own these two films but none of the others.
There is one that involves a character with the ability of telekinesis, which is actually a very interesting idea but the way it's handled is a bit unsatisfying.

Friday The 13th (1980)

The first one gets my vote. It's by far the best in the entire series because it really takes it time to develop the characters and overall creepy atmosphere.
You've seen Guy Standeven in something because the man was in everything.

7 wins because of the cool telekinesis girl, but X and FvJ aren't far behind it for me.

I don't think I've actually watched a friday movie all the way thru. I remember as a kid I watched a bit of one and all I remember is some lad in an alley fighting jason and he gets his head punched off, iirc. That is the only thing I remember about these movies I may have seen a bit of jason vs freddy too.

A Nightmare on Elm Street
is a decent film, but it isn't scary and the ending is quite weak. Robert Englund's stellar performance as Freddie Krueger is the film's strongest feature.

What's your opinion of the Elm Street Franchise?

They're all very badly done slashers, to be honest. I think the main reason that the first film took off is because it was novel, at the time, to see such a grimy film of this nature playing in mainstream theaters rather than grindhouse theaters. It is definitely not a good movie.
But, then again, the
Friday the 13th
series is still far better than most of the slasher series that followed it, like the truly godawful
Terrifier
movies.

Best one, hands down.
My password is password.

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My password is password.

X FTW
My password is password.