The MUST SEE scary horror movie of the moment is THE LAST HORROR MOVIE (2003). It's more disturbing than scary, but the twist at the end is a real jaw dropper!
There are lots of different types: suspense, slasher, zombie/monster...
It was already mentioned, but I'd like to give further props to House of 1000 Corpses. Rob Zombie's tribute to slasher movies of the 80's out-does itself.
I also really liked 28 Days Later. Part Return of the living dead, Part the Stand.
I thought the remake of House on Haunted Hill (with Geoffrey Rush) was pretty good.
The original Phantasm is also one of my personal favorites... although it's a little strange.
If you want something that's just plain disturbing, check out Johnny Got His Gun.
Here's my post from it: If you like the first Halloween (my favorite horror film), you should check out other Carpenter stuff, if you already haven't. The Thing (obvious) The Fog Christine Prince of Darkness They Live (not necessarily horror, but definitely funny) In the Mouth of Madness
Also check out some Wes Craven stuff: Last House on the Left (a must see for any horror buff) The Hills Have Eyes A Nightmare on Elm Street New Nightmare Scream 1 Scream 2
Peter Jackson has done some fantastic horror comedy with: Bad Taste Braindead (aka Dead Alive)
Other older stuff you should see: The Thing from Another World Suspiria I Spit on Your Grave The Wicker Man Texas Chainsaw Massacre 2 (funny and a decent sequel) Return of the Living Dead (funny) The Brood The Fly Videodrome Cronos Creepshow
For recent stuff, I second May and would add: Cube Bubba Ho-Tep From Hell (great atmosphere) Frailty (HIGHLY RECOMMENDED) My Little Eye 28 Days Later Cabin Fever Open Water (out now) Shaun of the Dead (out soon + highly recommended)
I don't know Italian horror very well (aside from some Argento), so I'll leave that to others. But I think this is an decent list to get started with.
1. Ringu (Japanese) 2. Juon (Japanese) 3. The Changling 4. The Woman in Black (BBC movie. Not gory, but plays with your head in a The Changling sort of way) 5. The Shining 6. The Babysitter 7. Happy Birthday to Me 8. My Bloody Valentine 9. Dark Water (Japanese Version) 10. Alice, Sweet Alice
One of the very few movies that REALLY scared me was The Omen, but that might have been because I was attending a Lutheran school at the time, and had been studying the book of Revelations in religion class. The teacher liked using scare tactics to make us behave.
I can't believe you mentioned this movie!!! I almost added this to my list too However, it wasn't the disappearing kids that scared me most... it was those darn Oompa Loompas!!! Those guys freaked me out!!! I had nightmares about them until I was in my 20's.
The only film that has ever creeped me out is Robert Wise's 1963 adaptation, The Haunting, starring Julie Harris, Claire Bloom, et al. Not to be confused with that dreadful 1999 adaptation. This film tops them all.
I don't find any horror movies scary now, but when I was young The Exorcist was pretty freaky. My Sandra loves being scared, Kubrick's The Shining is her favorite horror film, she's seen it the most times and it always creeps her out. Great film.
Jack Clayton's excellent The Innocents (1961) is a ghost story I found genuinely spooky and unnerving, still waiting for it to arrive on dvd.
This is one of the few that really scared the crap out of me. Just the music alone would send a shiver down my spine. I had the cd but could never listen to it.
Also Jaws, as I have never swam in the ocean the same since.