I find it interesting to look at the ebb and flow of horror movies through the past century. After Universal monsters of the 1930s (Frankenstein, Dracula, etc.), horror movies declined. Genre movies in the 1950s, were primarily science fiction themed with very little in the way of horror (The Fly, Invasion of the Body Snatchers). With drive-in classic I Was a Teenage Werewolf in the late 1950s, and the advent of Hammer Studios, the horror genre made a comeback. By the 70s, things started getting gritty (The Exorcist, The Texas Chainsaw Massacre and Last House on the Left), only to become glossy and tame again by 1990s (Jason X, I Know What You Did Last Summer, Scream). Then came the J-horror (The Grudge, The Ring ), the remakes (The Hills Have Eyes, The Omen, Texas Chainsaw Massacre), and torture porn (Hostel, Saw, The Devil's Rejects) in the new century. What does the future of horror filmmaking hold in store for the next few years, and what will be its defining characteristic? If movies like The Strangers (2008) are any indication, it will be a very dark (but interesting) ride.
If you enjoy movies like I Was a Teenage Werewolf, I strongly recommend Filmfax as a great resource. However, if you are bent towards the more horrific types like Hostel and The Exorcist, I would recommend Rue Morgue. And finally, if you enjoy the more obscure varieties (Mario Bava films, for example), check out Cinebeats.