Beyond The Door absolutely petrified me as a kid, and as a bandwagon film, and perhaps the most famous of the Exorcist ripoffs, gets good mention.
Local NY stations would run the commercial just a 10 o' clock when kids had to go to bed. And we all were affected by that nice little question that Juliet Mills gets to ask in this little scene:
Low budget, yes. But a true feeling of evil pervaded the possession scenes and made it a truly brooding and atmospheric film.
Other faves of mine:
Horror High aka "
The Twisted Brain"
Tombs Of The Blind Dead and it's sequels
Lucio Fulci's films, namely
Zombie 2 and
House By The CemeteryLet Sleeping Corpses Lie aka
Don't Open The WindowTales From The Crypt and
The Vault Of HorrorSuperstition (early 80's Italian movie.)
and many many more!