There are plenty of horror titles available on DVD that you should check out, but there also plenty of titles not yet available on DVD. Here's some movies that should be on digital.
Death Laid An Egg (1968)
Goofy title aside, this is a little know, psychedelic and all around strange Giallo film involving a man who owns a chicken factory. This needs to be on DVD for the premise alone.
Death Ship (1980)
A cult favorite from Canada, with a fun cast (George Kennedy! Saul Rubinek! Richard Crenna!) with a poster that "Ghost Ship" ripped off. The directors cut supposedly has some gruesome moments.
Joan Crawford overacts as only she can in this movie about murders in a traveling circus. With some fun deaths and an all around (unintetionally) campy tone, this one is lost for reasons beyond me.
A blend of Slasher and Giallo sub-genres involving a group of actresses being killed at a remote cabin by a slasher with a creepy old woman mask.
The Keep (1983)
Based on the acclaimed novel by F. Paul Wilson, and directed by Michael Mann, "The Keep" is one of those creepy 80's sleepers that deserves a DVD release. Plus, it has a score from Tangerine Dream!
Deadly Intruder (1985)
Actually, this sucks , but it has Danny Bonaduce having his head shoved through a TV, so for that it gets a minor pass.
William Friedkin directed this Horror/Drama about a liberal attorney (Michael Biehn) caught in a case with an insane serial killer (Alex McArther.) Not a particularly gory feature, but one that has should spark some interesting debate.
The Town That Dreaded Sundown (1976)
An Arkansas town is terrorized by a killer wearing a white hood in this Charles ("The Legend of Boggy Creek") B. Pierce cult favorite staring Ben Johnson and cult icon Andrew Prine.
It involves giant ticks, it was directed by Tony ("Hellbound: Hellraiser II") Randel, it was produced by Brian Yuzna, and it stars Clint Howard, Seth Green and Alfonso Riberio. Need I say more?
Wild Beasts (1984)
I haven't seen this one, but the premise (zoo animals on PCP go on a bloody rampage) is too great to pass up. And it's Italian!