The Hills Have Eyes
I tried to watch The Last House on the Left years ago and couldn't get through it. Not because of its unpleasantness or my squeamishness, but because of the bad acting. So I had always avoided The Hills Have Eyes, fearing that it would be more of the same. But I ended up wanting to watch it for some research I'm doing and I was (un)pleasantly surprised by how much I liked it.
It's definitely a "horror" movie, but watching it, I couldn't help thinking about how different it is from most other horror movies - especially current ones. There's some gore and general gruesomeness, but Wes Craven doesn't really focus on it (a la Seven) or fetishize it (a la The House of 1000 Corpses). His take on it seems much more matter-of-fact: it's upfront about the effects of violence, without reveling in them.
And though the movie has its share of suspense sequences (will the mutants attack? will the guy with the gun get back in time to use it?), creating suspense seems less important to Craven then ratcheting up the tension. It feels a little bit like a post-apocalyptic survival movie - Panic in Year Zero!, say - where the question isn't so much "What horrible thing will happen to these people?" and more "Given that they're facing this horrible thing, what will they be driven to do? To what lengths will they go to get themselves out of trouble?" (Hey, that also turns out to be one of the central questions of The Descent!)
More importantly, Craven doesn't make too much use of shock/scare/boo! moments, which may be the biggest difference between this movie and the current horror crop. What's shocking and horrific about The Hills Have Eyes is the situation itself: the brutal attack on the family that Craven refuses to make easy on us, by , say, sparing the likable characters or leaving out the survivors' grief.
Also notable: the "monsters" in this movie aren't really superhuman. This makes the movie feel a bit more like Straw Dogs, Deliverance, or Southern Comfort, rather than most slasher/zombie/monster flicks. But the knowledge that the stranded family members could sruvive (if they get their act together, self-defense-wise) makes things, in some way, much more horrible than if they were facing an unstoppable creature. I can only assume that The Last House on the Left works somewhat the same way and now I'm interested in giving it another chance. I'm also interested in checking out the remake of this movie, if only to confirm my suspicions that it's full of gore-for-its-own-sake, "boo"-scares, and other current horror cliches*.
One last thing: seeing a "real" grindhouse movie like this one makes me even less impressed with Planet Terror (I still like Death Proof, though). The Hills Have Eyes is an example of great B-movie filmmaking: Craven gets everything he can out of a fairly simple set up, without any needless excess. And, I'm not sure exactly how to put this, but the attention to the specifics of how the events unfold during the central R.V.-invasion sequence is pretty impressive. It shows a canniness and intelligence that is lacking from a lot of contemporary horror productions, which get by on big gestures rather than on smart details.
*Although, per this Sean Collins post, it probably isn't really a good idea to judge a movie before seeing it. FWIW, I think Hostel is all-over-the-place, though it has its moments.