[spoiler]Theatrical ending: When he walks downstairs after she starts screaming, rather than her walking back up the stairs dripping blood after stabbing him, she drags him back up with her and before you see her, she throws the body into the camera. She goes and stands over the lifeless body, looks at the camera, and jumps into it. It ends the movie on a climactic point, and leaves room for a sequel if they really wanted. That's about all it had going for it. For me, it was just too cheesy sounding.
Original ending: he walks downstairs, he gets stabbed, she comes back up with blood on her shirt, and sits at the side of the bed, rocking back and forth, as if possessed. A day passes, her friend comes over, you don't see anything but her friend screams and runs out (she found the boyfriend stabbed) -- 30 minutes later, cops show up, they walk upstairs, they find her and shine a flashlight on her. She comes out of her daze and is like "Wait, where is Nicah?" and runs at them; then, the ghost slams the door behind them and the cops startle and shoot her dead as she's walking to them. They go to look in the room and find nothing.[/spoiler]
I found it creepy, and when I went to sleep, it set in. It made me lose at least a few hours of sleep. =P