It's a tough question. There's great movies and terrible movies in both halves. I'm putting asterisks on those I think are among the best of each half. There are many I haven't seen, and many that are technically bad movies but I always enjoy watching them.

1970-74

House Of Dark Shadows
I Drink Your Blood
*The Vampire Lovers
Taste The Blood of Dracula
Scars Of Dracula
The Dunwitch Horror
The Wizard Of Gore
The House That Screamed
Count Yorga, Vampire
The Return of Count Yorga
Equinox
The House That Would Not Die
Cry Of The Banshee
Mark Of The Devil
Carnival of Blood
Bloodthirsty Butchers
The Body Beneath
*The Abominable Dr. Phibes
*Willard
Daughters Of Darkness
Vampyros Lesbos
Twins Of Evil
The Blood On Satan's Claw
*Let's Scare Jessica To Death
Lust For A Vampire
Lady Frankenstein
The Shiver Of the Vampires
Dracula Vs. Frankenstein
Blood And Lace
Zaat
The Corpse Grinders
The Velvet Vampire
Requiem For A Vampire
Don't Deliver Us From Evil
Werewolves On Wheels
A Taste Of Evil
Slaughter Hotel
Honey Britches
The Girl Slaves Of Morgana La Fey
Brain of Blood
Blood Legacy
The Headless Eyes
The Night God Screamed
The Vampire Happening
Sometimes Aunt Martha Does Dreadful Things
Blood Shack
Sweet, Sweet Rachael
*Last House on The Left
Tales From The Crypt
Dr. Phibes Rises Again
Dracula A.D. 1972
Frogs
Blacula
Virgin Witch
The Legend Of Boggy Creek
*Don't Torture A Duckling
Gargoyles
Blood Freak
The Gore Gore Girls
All The Colors Of The Dark
Demons Of The Mind
Vampire Circus
Children Shouldn't Play With Dead Things
Night Of The Dark Full Moon
Man From Deep River
Beware! The Blob
Private Parts
Something Evil
*Blood Spattered Bride
Grave Of The Vampire
Terror House
The Lady In Red Kills 7 Times
Blood Sabbath
Love Me Deadly
Night Of The Devils
Stanley
The Screaming Woman
Night Of 1,000 Cats
Fury Of The Wolfman
Evil Come Evil Go
The Slasher Is The Sex Maniac
Blackenstein
Enter The Devil
She Waits
Naked Girl Killed In The Park
Invasion Of THe Blood Farmers
Garden Of The Dead
Asylum Of Satan
The Rats Are Coming THe Werewolves Are Here
Frankenstein '80
Smile Before Death
Dr. Gore
Scream Bloody Murder
The Exorcist
Psychomania
The Wicker Man
Theater Of Blood
Flesh For Frankenstein
The Crazies
Torso
The Baby
A Virgin Among The Living Dead
Invasion Of The Bee Girls
Female Vampire
Satan's School For Girls
The Iron Rose
*The Creeping Flesh
Pigs
Tombs Of The Blind Dead
Cannibal Girls
The Sinful Dwarf
Dont Look In THe Basement
Baba Yaga
Seven Dead In The Cat's Eye
Schoolgirls In Chains
The Vampire's Night Orgy
Count Dracula's Great Love
The Devil's Plaything
Blood Orgy Of The She Devils
The Devil's Daughter
Death Smiles On A Murderer
Lemora
The Candy Snatchers
Horror High
Horror Rises From The Tomb
Hannah, Queen Of The Vampires
The Picture Of Dorian Gray
Warlock Moon
Scream... And Die
The Werwolf Of Washington
It Happened At Nightmare Inn
Godmonster Of Indian Flats
Mark of The Devil II
The House That Cried Murder
Curse Of The Devil
The Cat Creature
Scream Blacula Scream
Mystery In Dracula's Castle
*The Texas Chainsaw Massacre
*Black Christmas
It's Alive
Deranged
Messiah Of Evil
Blood For Dracula
Vampyres
Captain Kronos - Vampire Hunter
Bad Ronald
Beyond The Door
Lorna The Exorcist
Sexcula
Symptoms
Flavia THe Heretic
The Legend Of 7 Golden Vampires
Return of The Evil Dead
Frightmare
House Of Whipcord
Nightmae Circus
Killer Bees
Axe
The Ghost Galleon
All The Kind Strangers
The Eerie Midnight Horror show
Don't Open The Door
Scum Of The Earth
The Beast Must Die
*Death Dream
House Of Seven Corpses
The Thirsty Dead
The Cars That Ate Paris
Son Of Dracula
A Knife For The Ladies
Scream Of The Wolf
The Strange And Deadly Occurrence
Shriek Of The Mutilated
Help Me... Im Possessed

I'm also adding Oasis of Fear. I really like this movie and wish someone would get it onto Blu-ray. But I suppose because a certain actress was 16 when it was made and she had nude scenes, the USA considers it child pornography.

Also in this period you left out Kiss of the Tarantula, Lizard in a Woman's Skin, Perversion Story, Alpha Incident and Rana: The Legend of Shadow Lake.


1975-79

*Jaws
Salo
Profondo Rosso
*Picnic At Hanging Rock
Trilogy Of Terror
Ilsa: She Wolf Of The SS
The Devil's Rain
Snuff
Shivers
*Deep Red
The Stepford Wives
Frozen Scream
The Bloodsucker Leads The Dance
*Strip Nude For your Killer
Werewolf Of Woodstock
The Giant Spider Invasion
The Ghoul
Forced Entry
Lips Of Blood
Night Of The Howling Beast
Night Of The Seagulls
Exorcism
Criminally Insane
Satan's Children
Demon With Child
God's Bloody Acre
School Of Death
Carrie
The Omen
*Alice Sweet Alice
The Food Of The Gods
The Little Girl Who Lives Down The Lane
*Burnt Offerings
Grizzly
Eaten Alive
The Town That Dreaded Sundown
Blood Sucking Freaks
*God Told Me To
*Squirm
The Witch Who Came From The Sea
Island Of Death
Look What's Happened To Rosemary's Baby
Ilsa: Harem Keeper Of The Oil Sheiks
Drive In Massacre
Death Weekend
Sata's Slave
Embryo
*The Savage Bees
Spermula
Shocking Asia
Track Of The Moon Beast
Creature From Black Lake
A*P*E
Sisters Of death
Land Of The Minotaur
Rattlers
Seven Women For Satan
The Devil Master
Blood Bath
Blood Stalkers
Northville Cemetery Massacre
Death At Love House
The Miplitas Monster
Kidnapped Coed
Satan's Black Wedding
The Wife Killer
Blood Voyage
My Friends Need Killing
Suspiria
Eraserhead
The Hills Have Eyes
Exorcist II
Emanuelle And The Last Cannibals
Jungle Holocaust
*The Incredible Melting Man (I know it's terrible but it's just so much fun)
Day Of The Animals
Audrey Rose
Death Bed: The Bed That Eats
Blue sunshne
Prey
Bad
Alucarda
The Last House On Dead End Street
Ilsa: Tigress Of siberia
Ilsa: The WIcked Warden
Snowbeast
The Mighty Peking Man
Satan's Cheerleaders
The Haunting Of Julia
Love Letters Of A Portugese Nun
The Child
The Spell
Return To Boggy Creek
Meatcleaver Massacre
Keep My Grave Open
Whiskey Mountain
Ghosts That Still Walk
The Witches Of Pendle
*Halloween
I Spit On Your Grave
Dawn of The Dead
Damien: Omen II
Magic
The Evil
Faces Of Death
The Legacy
The Sentinel
Rabid
Kingdom of The Spiders
Empire Of The Ants
House
Tentacles
Count Dracula
Watch me When I Kill
Shock
Cathy's Curse
Dead Of Night
The Crater Lake Monster
Attack Of The Killer Tomatoes
Slave Of the Cannibal God
Martin
Nurse sherri
It Lives Again
Alien Zone
Vampire Hookers
The Grapes Of Death
The Initiation Of Sarah
Devil Dog: The Hound Of Hell
The Alien Factor
Helga: She Wolf Of Stilberg
Class Reunion Massacre
Inquisition
Mardi Gras Massacre
Killers Moon
Spawn Of The Slithis
Damned In Venice
Die Sister die
The World Beyond
Hallucinations of a Deranged Mind
*Alien
*Salem's Lot
The Amityville Horror
Phantasm
*The Brood
Nosferatu: Phantom der Nacht
Zombi 2
Tourist Trap
The Evictors
The Driller Killer
*Don't Go In The House
Beyond The Darkness
Killer Nun
*When A Stranger Calls
Fascination
Savage Weekend
Thirst
The Day Time Ended
Dominique
Up From The Depths
Prophecy
Satan's Wife
Screams Of A Winter Night
Savage Water
Weasels Rip My Flesh
The Hollywood Strangler Meets The Skid Row slasher
*The Meateater (for the same reason as The Incredible Melting Man)