The House of the Devil is a really great revisiting of the 70's Satanic cult movie. It's even shot using some "Instagram" 70's filter and using a lot of old camera techniques which I thought might end up being too gimmicky but ended up adding a lot to the movie.
Pontypool is a really great zombie movie, in the vein of the original Dawn of the Dead. It's also a new enough take on the zombie/infected genre that it is actually quite clever, also poor man's Lance Henrickson does an incredible job in it (Stephen McHattie, shitty way to classify the guy since he's a far superior actor but I always think that he's Lance Henrickson when I first see him).
Another one with McHattie in it, albeit a less major role, is Exit Humanity. Most people that I've recommended it to haven't liked it but they haven't been able to really give a reason why so I think that it just might be a genre specific taste movie. It's basically 28 Days Later but set after the Civil War.
Hell is a pretty good movie. Subtitled and it has a similar vibe to The Road but it definitely tries to deal more with a smaller part of the effects of the downfall of society rather than the all encompassing "we are basically all pieces of shit" that McCarthy likes to hammer into his stories.
Absentia is a really well put together monster movie that follows all of the classic rules of building tension and does it well enough that you really don't notice a lot of small places where it starts to lead the story. Pretty much turns into an all around creepy movie by the end.
Session 9 is the quintessential asylum movie that has atmosphere and good pacing perfected down to a science. It's a bunch of guys that are usually supporting cast in US movies but they all pull off their roles incredibly well here.
Grave Encounters is the quintessential asylum movie that is heavy on visuals and cheap scares but it does a really good job with what it sets out to do. I could even look past the found footage style of it and would recommend it as a good horror movie to just about anyone. A very claustrophobic feeling the entire movie. Grave Encounters 2 is complete shit and should be forgotten about.
The Shrine ended up being, surprisingly, really good. It starts off and it seems like it might be another Hostel but it takes a turn and doesn't look back. A good "pursued by crazy cultists/villagers" movie
Most of the Masters of Horror series from HBO(? might have been Showtime) are really great shorts. John Carpenter's two entries are, by far, my favorites and if you watch just one of them check out Cigarette Burns.
Chop and Strigoi are two really good funny horror movies. Not much else to say than they have some great dark comedy.
The Possession of David O'Reilly is really weird and has some amazing creature design. It really fucks with pacing a lot which does a good job of keeping you on your toes and also anticipating the next really strange thing to happen. I would say it's a bit like the camera following Danny's big wheel in The Shining you get to k now that crazy shit is around the corner before you get to see it then you get to watch the movie drag you into that crazy shit.
There are probably a ton more and I think that all of these are still on Netflix but that's all that I can remember right now.