Yeah, for the OP, if you like Lovecraft, I also recommend In the Mouth of Madness as the best Lovecraft movie, even if not a direct adaptation. There is also a short B&W movie version of Call of Cthulhu which is worth watching made in the last few years by a Lovecraft society. Another John Carpenter movie worth catching is Prince of Darkness.
Dario Argento is good and violent. Suspiria, Creepers, the one with the decapitating murderer.... There's an old movie, Dead and Buried, for those who like that sort of thing. Foreign movies are good for gore, if anyone likes Argento then Lucio Fulci was up that alley somewhat.
For Stephen King adaptations, of course Shining is outstanding, Silver Bullet is underrated, Christine, Cujo, Sometimes They Come Back, I think a few of those are worth watching, particularly It. "It" was a made for TV movie, but it still holds up for me.