Birdemic: Shock and Terror
Alright, alright, maybe not that one.
Lemme go through my big list of horror movies (yes, I keep track on the horror movies I've watched because I'm mental) and see if I can find anything worth recommending.
(trying to avoid the most well-known movies and also shit that I like even though it's undeniably awful)
Candyman (obligatory mention because it's one of my favorite slasher movies of all time)
The Crazies
Dead Birds
Dead Snow
Insanitarium
(Jack Ketchum's) The Girl Next Door
The Loved Ones
Martyrs
The Mist
The Poughkeepsie Tapes (I dunno, I didn't find it scary, but I can see why other people would)
Sauna
Splinter (seconding TheFunPolice - it's a great movie)
Trick 'r Treat
Look them up first, though. My taste in movies is infamous for being pretty damn questionable and I wouldn't even take my own word for these movies actually being good. Especially seeing how it's been a while since I saw some of these, so my memory may be making them up to be better than they actually are.
(It's 13 out of some 400 movies, so you'll have to forgive my memory)