Interesting answers from everyone! I agree with pretty much everything that has been posted. The one that we disagreed on for a bit was Psycho - I said it's absolutely a classic, he didn't exactly disagree but said that Hitchcock's other films like The Birds far outshine it. Eventually we came to the agreement that which one is "better" (which is subjective) doesn't affect whether the other is a classic or not. He was also a little iffy on The Exorcist, but again that came down to "just because you think others are better doesn't mean it's not a classic"
We didn't come up with Carrie, Alien, Evil Dead, Children of the Corn or House on Haunted Hill which I would say are definitely all classics. The rest were on our list
There was a great moment when I was reading off replies and read "Nightmare on Elm Street", to which he says "Oh please, that's not a horror film" which resulted in a bunch of confusion from both of us while I insisted it definitely was, and he said it definitely wasn't... till he said "it's a holiday movie!" and I realized he was thinking of Nightmare Before Christmas
lol. Especially since a bit earlier we had already agreed Nightmare on Elm Street was definitely a classic horror film.
I really need to re-watch Halloweentown. I haven't seen it since I was a kid!