I first saw Childs Play when I was 10, scared the life out of me.

A Nightmare on Elm Street
Children of the Corn IV: The Gathering
Final Destination
Hell Night
Scream

these flicks scare me pretty good enough.
and never get to tire of watching them ether.
and much much other faves as well.

Carrie was the first film that scared the bejesuz out of me. But I was young then, so it doesn't have the same fright factor as it once did. Still an awesome film in my book though.

You didn't think that the Texas Chainsaw Massacre was scary??? dang. Have you seen Stephen King's "It"?

I'm gonna have to go with Blair Witch. That movie is terrifying if you let it take you in. I also don't really get scared by that many movies. The things that scare me are Chris Cunningham videos, check out "Rubber Johnny" and his Aphex Twin video for "Come to Daddy". Those are really creepy, that guy should be doing movies.

Yes, I saw "It". That movie definately creeped me out. Creeped me out as a kid and the clown still gets to me now.

It is pretty scary. I thought the original TCM was aswell.

On the subject of Stephen King, I think Misery can be pretty scary at times, just how possible it is.

Top 10
 

These are the scariest movies I have ever seen...

10. "The Shining" (1980)
9. "Friday the 13th" (1980)
8. "The Descent" (2005)
7. "The Others" (2001)
6. "Welcome to the Jungle" (2007)
5. "[rec]" (2007)
4. "The Exorcist" (1973)
3. "The Ring" (2002)
2. "Session 9" (2001)
1. "The Blair Witch Project" (1999)

There's not many that have truly scared me. Though, a few have gotten a good ways under my skin.

If you want to get scared or feel the closest to being scared as possible, I highly recommend these:
1. Wait Until Dark may take a while to get to the "scary" parts, but the whole ending itself of the film is pretty damn terrifying. Beware of the Alan Arkin "jump across the screen" scene.;)
2. The Picture of Dorian Gray
3. Deliverance
4. The Shining
5. The Exorcist

I'm sure you've seen or at least heard about the last two though.

For a more modern horror film, I'd recommend The Mist for the harrowing aura it contains.