Friday the 13th

Friday the 13th (A-)
Friday the 13th, Part II (A)
Friday the 13th, Part III (3D) (B-)
Friday the 13th, Part IV: The Final Chapter (B+)
Friday the 13th, Part V: A New Beginning (C+)
Friday the 13th, Part VI: Jason Lives (B-)
Friday the 13th, Part VII: The New Blood (D-)
Friday the 13th, Part VIII: Jason Takes Manhattan (C+)
Jason Goes to Hell (F)
Jason X (C)
Freddy vs. Jason (C-)

Suggested viewing:

Friday the 13th
Friday the 13th, Part II
Friday the 13th, Part III (3D)
Friday the 13th, Part IV: The Final Chapter
Friday the 13th, Part V: A New Beginning
Friday the 13th, Part VI: Jason Lives

A Nightmare on Elm Street

A Nightmare on Elm Street (A)
A Nightmare on Elm Street, Part 2: Freddy's Revenge (C+)
A Nightmare on Elm Street, Part 3: Dream Warriors (B)
A Nightmare on Elm Street, Part 4: The Dream Master (C-)
A Nightmare on Elm Street, Part 5: The Dream Child (F)
Freddy's Dead: The Final Nightmare (D-)
Wes Craven's New Nightmare (A)
Freddy vs. Jason (C-)

Suggested viewing:

A Nightmare on Elm Street
A Nightmare on Elm Street, Part 2: Freddy's Revenge
A Nightmare on Elm Street, Part 3: Dream Warriors
Wes Craven's New Nightmare

Halloween

Halloween (A)
Halloween II (B-)
Halloween III: Season of the Witch (F)*
Halloween IV: The Return of Michael Myers (A+)
Halloween V: The Revenge of Michael Myers (D)
Halloween: The Curse of Michael Myers (D-)
Halloween H20: 20 Years Later (A)
Halloween Resurrection (C+)
Halloween (2007) (C)

* Halloween III has nothing to do with the rest of the series

Suggested viewing:

Halloween
Halloween II
Halloween H20: 20 Years Later

OR

Halloween
Halloween II
Halloween IV: The Return of Michael Myers

Hellraiser

Hellraiser (B-)
Hellbound: Hellraiser II (C)
Hellraiser III: Hell on Earth (D-)
Hellraiser: Bloodline (B-)
Hellraiser: Inferno (C)
Hellraiser: Hellseeker (C-)
Hellraiser: Deader (D)
Hellraiser: Hellworld (D+)

Suggested viewing:

Hellraiser
Hellbound: Hellraiser II
Hellraiser: Bloodline

The Living Dead series

Night of the Living Dead (1968) (C-)
Night of the Living Dead (1990) (A+)
Dawn of the Dead (1978) (A)
Day of the Dead (B-)
Dawn of the Dead (2004) (B+)
Land of the Dead (C)
Day of the Dead 2: Contagium (F)

Suggested viewing:

Night of the Living Dead (1990)
Dawn of the Dead (1978)
Day of the Dead
Land of the Dead

OR

Dawn of the Dead (2004)

The Texas Chainsaw Massacre

The Texas Chainsaw Massacre (1974) (B+)
The Texas Chainsaw Massacre 2 (F)
Leatherface: Texas Chainsaw Massacre III (C)
Texas Chainsaw Massacre: The Next Generation (D)
The Texas Chainsaw Massacre (2003) (C-)
The Texas Chainsaw Massacre: The Beginning (2006) (C)

Suggested viewing:

The Texas Chainsaw Massacre (1974)
Leatherface: Texas Chainsaw Massacre III

The Exorcist

The Exorcist (A+)
The Exorcist II: The Heretic (F)
Exorcist III: Legion (B)
Exorcist: The Beginning* (D)
Dominion: Prequel to the Exorcist* (D)

Suggested viewing:

The Exorcist
Exorcist III: Legion

* The last two movies are in essence the same movie. After Dominion was made, the Hollywood bigwigs decided they didn't like it and remade it changing a few things here and there; most notably they changed the possessed person from a native boy to a hottie female nurse. Neither movie is very good, but Dominion is probably slightly better. The Beginning does do a better job of explaining a few things from the first Exorcist though. Probably best to just not watch either.