I found "The Changeling" to be excruciatingly dull and not the least bit deserving of its reputation.
"The Omen" is pretty stupid. Decent concept, shitty execution.
Barely remember "The Mothman Prophesies" but at the time I considered it one of the worst films I'd ever seen. The legend of the mothman is somewhat intriguing but the movie's an amateurish bore- missed opportunity.
I recently asked for horror movie recs because I'd been disappointed by a couple horror films I'd watched and "The Conjuring" was one of them. James Wan makes Craven look like Hitchcock IMO.