Halloween is simply one of the greatest horror films of all time.  Released in 1978, this film is a great example of creating (or re-creating?) a genre is a way that lasts a very long time.  There is no doubt in my mind that Friday the 13th, Nightmare on Elm Street and a host of other films would not have been possible without it.  It also kicked off an odd genre, the "holiday murder movie" genre.  I am sure that most people remember Friday the 13th, April Fool's Day, My Bloody Valentine, etc.
Halloween was directed by John Carpenter and written by Mr. Carpenter and Debra Hill.  They also wrote The Fog together.  The writing is very strong as is the attention to detail.  The overall mood of the film is very dark and creates a tension that really draws you into the story.  The film had a total budget of $325,000, which means that Halloween is actually a "low budget" film.  It has since grossed more than $45,000,000 in the U.S. alone.
The film begins in 1963 in the town of Haddonfield, Illinois.  Six year old Michael Myers murders his sister Judith on Halloween night.  He is arrested and incarcerated at the Smith's Grove facility.  The only person that really seems to understand him is Dr. Sam Loomis, a psychiatrist at the facility.  Fifteen years after his arrest, Michael Myers breaks out of the facility.  Dr. Loomis then makes the trek to Haddonfield to warn the citizens of impending evil and attempts to help with finding Michael.  Through the events that follow, it is safe to say that the facility did not cure Michael.

The horror genre saw several major changes in a ten year period.  First, Romero released his iconic Night of the Living Dead in 1968 and turned the horror world upside down.  Tobe Hooper then took horror to a whole new level in 1974 with Texas Chain Saw Massacre.  The horror genre owes no less to Halloween than the two previously mentioned films.  Halloween's contribution spawned a genre that lasts today, more than 30 years later, and still makes for a very effective scare when done correctly.