I'm on my own here I suppose then - I reckon Scream's the best scary movie ever. It manages to take the horror movie conventions, completely dismiss them all, and yet still manage to be a scary movie in its own right. And a good twist at the end as well, which does add up. The other two are also worth watching, although they're not quite as immediate, and are really only for fans of the first.
Incidentally, the "you hit me with the phone" bit was apparently an ad-lib - he was actually genuinely hit with the phone after it slipped out the other guy's hand, but they kept 'in the moment', as it were.