So what was the Conjuring about? It's the standard 'family moves into house and discovers it's haunted' plot, which makes you wonder. Wtf do families keep moving into creepy, derelict houses in the middle of nowhere? Other than the fact that if anything happened (non-paranormal) it would be pretty hard to get help, there's also the fact that most houses like that apparently haunted. In movieland.
So yeah, haunted house. I'm going to be honest, I found the first part scarier than the second. But that's mostly because the doll is freaking creepy. I suspect I've been traumatised by Chucky when I was younger so that may just be some lingering psychosomatic effects from that period. But other than that, The Conjuring is a fairly standard flick in the sense that there is really nothing new that you're going to see there.
From a writers/directors stand point, or even a genre-savvy movie-goer, it's somewhat obvious (even painfully obvious) at times, just what is going to happen. You just know when certain things will happen or when is the best moment to scare the audience. For example, when the mother gets trapped in the basement, you just know spooky shit is going to go down and you're kind of mentally prepared for it. I guess.
However, that doesn't really detract from the movie's scariness apparently. I'm not a great judge of horror films because frankly, I've been scared to death by quite a few when I was younger and I find korean/japanese horror to be scarier anyway, but I do know quite a few people were flinching away from the scenes on screen.
My only real issue is again; no one dies in the film. For a demonic hell-spirit who keeps muttering "I'm going to kill you all, ALL OF YOU", the ghost actually...kills no one. I can understand that it's basically trying to pull off a certain combo that apparently gains it more hell brownie points but at some point, you're going to have to go 'Okay, this is not working. Let's just kill everyone NORMALLY'. But again, I can get where that's coming from because I have the same issues with fighting games/wargames/etc where I obsess over doing something in a PARTICULAR way that sometimes ends up costing me the game.
So overall, I'd say the conjuring is a decent film to watch. If you watch it with a female. Or females; plural. Make sure to sit in the center.