For comedy horror I think the Scream franchise is great. Silly gore - Wrong Turn, Final Destination etc. But for actually creepy, jump scares that might make you scared to go for a wee in the night…Insidious, The Nun, The Ring and The Grudge have always terrified me. The Smile films are creepy as fuck too.
There are a couple of really chilling films that are scary because they could potentially happen. Eden Lake is one. Love a good horror movie but there are so many different sub genres I have to be in the right mood for each.