This is probably my least favourite horror franchise, although I do like them enough to own all of them. I'm not even a HUGE fan of the first movie, I like it but don't LOVE it like everybody else does. I find the whole franchise is just a lot of screaming, crying, and torturing (It's pretty much the first torture porn film).
That being said, I went with the remake with The Beginning not too far behind. They are probably the only ones similar in tone to the first film, the other ones are just ridiculous and cheesy.