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).