For my money, the original Tomb of Dracula is still the best horror comic to ever show up at a newsstand.  From 1975, The cover of Tomb of Dracula #41 is a classic.  Credit for this goes to Gene Colan, Tom Palmer, and Gaspar Saladino.

Previous Great Moments In Comic Book History:

1. Winchester Before Winchester: Swamp Thing Vol. 2 #45 “Ghost Dance” 
2. The Avengers Appear on David Letterman
3. Crisis on Campus
4. “Even in Death”
5. The Debut of Man-Wolf in Amazing Spider-Man
6. Spider-Man Meets The Monster Maker
7. Conan The Barbarian Visits Times Square
8. Dracula Joins The Marvel Universe
9. The Death of Dr. Druid
10. To All A Good Night
11. Zombie!
12. The First Appearance of Ghost Rider
13. The First Appearance of Werewolf By Night
14. Captain America Punches Hitler
15. Spider-Man No More!
16. Alex Ross Captures Galactus
17. Spider-Man And The Dallas Cowboys Battle The Circus of Crime
18. Goliath Towers Over New York
19. NFL SuperPro is Here!
20. Kickers Inc. Comes To The World Outside Your Window
21. Captain America For President
22. Alex Ross Captures Spider-Man
23. J. Jonah Jameson Is Elected Mayor of New York City
24. Captain America Quits
25. Spider-Man Meets The Fantastic Four
26. Spider-Man Teams Up With Batman For The Last Time
27. The Skrulls Are Here
28. Iron Man Meets Thanos and Drax The Destroyer
29. A Vampire Stalks The Night
30. Swamp Thing Makes His First Cover Appearance
31. Tomb of Dracula #43
32. The Hulk Makes His Debut
33. Iron Man #182
34. Tawky Tawny Makes His First Appearance
35. Tomb of Dracula #49
36. Marvel Publishes Star Wars #1
37. MAD Magazine Plays Both Sides
38. The Cover of Green Lantern/Green Arrow #85
39. LBJ Stands Up For The Hulk
40. Chamber of Chills #2