I have a lot of loose-end ideas about this subject, so I think I will just bounce around here a little bit. So, this may not follow any consistent pattern. The horror film genre has long been a sub-industry in of itself, as it has been something basically "apart" from mainstream Hollywood. Every year, going back to the 70s, this genre has produced many low-budget films; as evidenced by all of those late-night movies on second-tier cable networks like Cinemax since the 80s, or the seemingly endless stream of direct-to-video movies that you probably saw in the now disappearing video rental stores.
It has become much more mainstream in recent years, but the independent element is as strong as ever. I have always enjoyed horror movies. I'm not as much for zombie or slasher films. I prefer paranormal or mystery-based thrillers. Horror films seem to be a refreshing creative license for the producers to take chances, be overzealous, be silly, be shocking--without the worry of too much artistic criticism. Of course, there is the more finely artistic element to it. The rest mostly fall into the category of exploitation films.
The Europeans have been at least as much the early pioneers of this genre. The 1922 silent German horror film 'Nosferatu' is regarded as "an influential masterpiece of cinema," and clearly a forerunner of the early classic American horror films. The "Hammer films" from the UK were very popular in the United States going back many decades, especially in the 60s and 70s. Recently I watched again the Hammer film 'Tales from the Crypt (1972), and it was very eery. I think that someone who is not a particular fan of this genre would probably enjoy being creeped out by it. It was eerily though-provoking.
The "cabin in the woods" concept has long been a favorite backdrop; as it forms a little world unto itself... in which the story unfolds. Just last week, the Independent Film Channel had a double-feature of just this theme: 'Cabin Fever' (2002), an American film; and 'The Last House in the Woods' (2006), an Italian film. This popular horror flick was something like an Italian version of 'The Texas Chainsaw Massacre'. I don't know much about Italian horror in particular, but I know that Dario Argento has long been a big name in this genre. I recall watching some of these films as a kid, often late at night, and wasn't even aware that they were from Italy... or Germany, Spain, etc. I specifically remember one called 'Bay of Blood' (1971), directed by Mario Brava.
I recall one time a friend who really knows a lot about the Italian horror genre mentioning that Anna Falchi had appeared in many of these films and is well-known in Europe as a "scream queen." In the United States, to me, Linnea Quigley is one that comes to mind in this category. Elizabeth Kaitan is another one that I really remember. American Theaters which played the exploitation films within this genre were called "Grindhouse" theaters. I don't know of any theater that specifically fits that description anymore, but it's a curious concept. One exploitation horror film which I thought was eerily artistic was Rob Zombie's 'House of 1000 Corpses' (2003).
When I was a child in the Bay Area, there was a program on KTVU called 'Creature Features' (1971-1984). Actually this apparently was a syndicated program, and this was our locally-hosted broadcast. This was a much bigger cultural element since there weren't the cable channels, internet, video games, IPad's, etc. as there is now. This was even before VCR's! Locally it was hosted by the late Bob Wilkins, who was a unique type of host who always kept everyone up-to-date on the horror or similar conventions that would come around. One movie that was frequently broadcast was George Romero's 'Night of the Living Dead' due to its popularity. That movie, and Romero's films since, have directly led to this "zombie craze" that we see today.
I had mentioned earlier the 1922 move 'Nosferatu'. In 2000, there was a British "remake" of a sort called 'Shadow of the Vampire', staring John Malkovich and Willem Dafoe. I thought it was worth a mention because it was somehow an acknowledgement of the whole of this element of our culture since 1922... and it was a good movie. Interestingly, it was a fictional horror movie about the "making" of the original film in Slovakia.