Best:

1. Halloween (orginal)
2. Scream (first and second films)
3. Candyman (First and second films)
4. Nightmare on Elm Street (original)
5. Friday the 13th (orginal and first two sequels)
6. Child's Play (first and second films)
7. Carrie (orginal)
8. The Exorcist (original)
9. Final Destination (First and second films)
10. The Birds (orginal)
    Worst:
11. Candyman 3: Day of the Dead
12. The Birds II: Land's End
13. Halloween Resurrection
14. Jason X
15. The Rage: Carrie 2
16. Friday the 13th Part VIII: Jason Takes Manhattan
17. Friday the 13th Part V: A New Beginning
18. Jason Goes To Hell: The Final Friday
19. Halloween: The Curse of Michael Myers
20. Scream 3

best:

1. A NIGHTMARE ON ELM STREET (original)
2. CARRIE (original)
3. HALLOWEEN (original)
4. THE FOG (original)
5. PSYCHO (original)
6. THE EXORCIST
7. DAWN OF THE DEAD (original)
8. NIGHT OF THE LIVING DEAD (original)
9. THE TEXAS CHAINSAW MASSACRE (original)
10. SUSPIRIA
    worst:
11. SILENT NIGHT, DEADLY NIGHT 3: BETTER WATCH OUT
12. FEARDOTCOM
13. CABIN FEVER 2: SPRING FEVER
14. BLOOD CULT
15. HOWLING: NEW MOON RISING
16. SLEEPSTALKER
17. APRIL FOOL'S DAY (remake)
18. SLEEPY HOLLOW HIGH
19. DO YOU WANNA KNOW A SECRET?
20. THE FINAL DESTINATION
    "Cinema is everything to me. I live and breathe films I even eat them!"

• Lucio Fulci

It's been a while since I posted this. And I changed my mind in 6 years, this is what I think about this movies now:
best
1-A NIGHTMARE ON ELM STREET (Still great)
2-CANDYMAN (Still great)
3-HELLRAISER (Still great)
4-FRIDAY THE 13TH AND SEQUELS (all sequels??? WTh?= The first 4 and part 7 are the best but not ewven in my top 50 now)
5-THE OMEN (Still great)
6- ROSEMARY'S BABY (Still great)
7-IN THE MOUTH OF MADNESS (Still great)
8-SAW (it's good)
9-TEXAS CHAINSAW MASSACRE (ORIGINAL AND REMAKE) (Original: Still great)(Remake is mediocre)
10-DAWN OF THE DEAD 2004 (just ok)
Phoenix Genma Ken! Hou Yoku Ten Shoo!

Alrighty. This is quite difficultI'm going to go for horrors and thrillers.
Candyman 1&2
High Tension (excellent!)
Chainsaw Massacre - The Beginning (prequel from 2006)
Halloween H20
Texas Chainsaw Massacre
Silence of the Lambs
Seed of Chucky (for the comedy)
Basic Instinct
Stigmata
The Prophecy 2
WORST

1. Candyman 3 (worst film of any genre EVER made)
2. The Omen (whole trilogy. It really bored me)
   Can't really think of any others off the top of my head
   I definately recommend 'High Tension' though! It's brilliant. It is best to watch it with a friend, because it will have you talking for hours afterwards!
   -Dix
   Don't knock it til you've tried it ;o)