I am just waiting for the Piranha 3-D movie which is something very different and Children never can't see this movie because its with lot of dangerous scene which seems horrible..
you should watch the last exorcism this is coming soon and I have seen the promos movie is looking too good.....
Since most horror films have gone rubbish since ...recently, I'd go for a good old Nightmare on Elm Street !
Most people know what to expect when they watch a new horror movie, so it doesn't scare them as much. New horror movies also never focus on characterization, like getting to know or care about the characters, so when something bad happens to these people we don't care.
Orphan, Splice, The Fly, Wolf Creek, The Last House on the Left, Haute Tension, Inside, Martyrs, The Human Centipede, The Exorcist, The Thing, Halloween, The Eye...for starters.
I would recommend REC (english version, not original spanish one though it's very good but I'm assuming you don't like subtitles heheh). I was tense the whole movie and I screamed a couple times scaring the life out of the whole movie theater lol! Honestly REC is one of the best horror movies I've seen since Freddy Krüger (I'm into classics heh). Hope it helps