I second this. It is a fabulous movie. Has Guy Pearce and Robert Carlyle.
Marc forgot to mention Vampires. There are Vampires. 
The Human Monster, starring Bela Lugosi.
Vampyres also known as Dracula’s Daughters. Not much blood, but nice boobs.
Right At Your Door is an especially effective little thriller that’ll have you running to the store to stockpile ducttape and pvc sheeting before the credits roll.
Timescape
Not really technically a horror film, possibly a thriller. A Time Travel Thriller, maybe.
Not really that obscure, but eXistenZ is a little trippy mindfuckity.
The 1979 Werner Herzog remake of NOSFERATU, slow-moving but chilling & I thought rather lovely, like a ballet of the grotesque. Stars Klaus Kinski & Isabella Adjani.
My recommendations for (A) and (C) you’ve already seen (**A Tale of Two Sisters ** and Jacob’s Ladder, although I don’t think the latter can be considered obscure.)
But I’ve got a recommendation for (B) that you’ve probably never seen: **The ** Seventh Curse. From a review I wrote for another site:
Click here for more info and my full review (scroll down).
Thanks for the reply…it was actually me (the OP) that brought up Dog Soldiers and Session 9, and I’ve seen the original Funny Games…going to put Dead Alive on the queue though, thanks!
Excellent! Thanks for the recommendation!
*Liquid Sky
Eraserhead
Bad Robert *(or Bad Richard or Bad Roger or something like that) – nutjob has secret room in family house messes up the homeowners’ lives
I forget the title, but It’s something like Frankenstein vs. Dracula – speaks for itself
suburban Nightmare, only because it got me an IMDB entry.
Bad Ronald. I’ve never seen it but I have heard of it.
Actually, Dracula vs. Frankenstein was the name of it. I have seen it. It has the last performances of J. Carroll Nash and Lon Chaney Jr., and also includes Russ Tamblyn & Uncle Forry Ackerman in the cast.
NOT a good film! 
But amazingly enough, available on DVD!
BRAIN DAMAGE is back in print on DVD!
Oh, yeah - almost forgot The Final Terror - psycho stalks campers in the redwoods, and its NOT dumb like Friday the Thirteenth. See Darryl Hannah get her thoat cut and survive! :eek:
Many of my faves listed here already, esp Carnival of Souls, The Changeling, and the original The Haunting.
I remember being terrified (as a kid) by The Tingler. It’s a kitschy B movie, but it’s got Vincent Price–what’s not to like?
Many years later, Red Rock West, which is much more noir than a horror film, gave me nightmares with one particular burial scene. <shivers>
Thrillers
Alexandra’s Project is a great little Aussie thriller. Disturbing on many levels.
Three Days Of The Condor - Brilliant Redford spy thriller, with the added bonus that all the espionage tricks in it are plausible.
A couple of great Walter Hill gimmick thrillers -
The Driver - a seventies existential noir heist flick.
Southern Comfort - a brilliant Vietnam metaphor
…and a couple of oldies
The Set-Up - a real time character thriller with Robert Ryan brilliantly authentic as a washed up boxer defying the mob.
Night of the Hunter - Uncategorizable movie about a couple of plucky kids trying to escape Robert Mitchum’s evil Preacher. Features Silent screen great Lilian Gish as a kindly Grandmother type with a shotgun.
Horrors
The Night Flier - Nice little B-movie with Miguel Ferrer as a tabloid reporter trying to track down a vampire attack small airports. Has a pitch-black vein of humour running through it.
Black Christmas (1974) - Pre Halloween slasher flick with another black humour vein. Bonus in that the stalker in this is genuinely scary.
Dellamorte Dellamore (Cemetary Man) - Surreal zombie horror comedy with Rupert Everett as a Cemetary worker dealing with the undead. Also features the rediculously hot Anna Falchi, as the girl Everett keeps accidentally killing.
Does anyone remember Midnight Offerings, with Mary Ingalls as the “bad witch” and Erin Walton as the “good witch”? 
Indeed. I feel the same way about Driven.
In the Mouth of Madness
another vote for **Dark City **
Cube (or was it The Cube?)
Donnie Darko
Annnndd…for a horror that’s also a comedy - They Live
For crawly suspense, I highly recommend Duel, an early Spielberg offering in which you can clearly see his coming brilliance (and that of Dennis Weaver, his put-upon protagonist). Best bad guy ever- a big fucking truck.
Although, sadly, the final shot is repeated almost exactly in a later Spielberg film- Jaws fans will recognize it immediately.