The first Omen was pretty cool. A slightly original take on an ancient concept, pretty well executed. The second one was basically made because the first one was so popular, but it was alright, and the third one was just kinda bad. I remember even then watching Sam Neill and thinking how hard he's trying to sound ominous and threatening and The Son of Satan, but he just didn't have the gravitas to pull it off.
I still remember that last line, though, and thought it was almost clever. "You have won... nothing."