The original Prom Night with Jamie Lee Curtis is worth seeing, to me it's a classic slasher film even though a lot of people thought it was rubbish. If you mean the remake, don't bother wasting your time, watch some other horror.
Teeth I have yet to see this, suppose to be rather good.
I recommend The Orphanage, and [REC] if you haven't seen the two films yet. Brilliant films. Unless you want lots of gore then maybe not...
Or The Descent!