"The Conjuring" is a very good movie, and as a horror film enthusiast, I'd say it's easily the best one of the 21st century. What makes it so good is the acting, which is great from the major characters to the children to the minor characters. Good acting is extremely rare for a horror film, because the producers usually cover up bad acting with gore, blood, and violence. The Conjuring is completely free of gore, violence, sex, and foul language, making it a rarity for any film these days, regardless of genre. It's a horror film in the classic sense; completely different from Hostel, Human Centipede, Texas Chainsaw Massacre, etc. I'd say the films that come closest in comparison are "Insidious" and "Paranormal Activity."
The Conjuring is allegedly based on a true story. Of course, I'm sure Hollywood changed the storyline a bit, but in any case, it gives us a very realistic look at the work and experiences of real people (Ed and Lorraine Warren and the Perron family).
I'd say it's definitely worth checking out. It has an 8.1 out of 10 rating on IMDb and 85% out of 100 on Rotten Tomatoes; extremely high marks for not just a horror movie, but a movie from any genre! It didn't get that for no reason. And yes, as a previous poster said, ignore the comments about a priest being at a theater and people sleeping with Bibles. If you get that disturbed by a movie, chances are your mental health was in a very poor state beforehand.
Saw it last Saturday!