My foster daughter has pierced ears and kept losing earrings.  She was really nervous about the holes closing up, so it became kind of a high-maintenance activity.  These have been in her ears for over a month and even though periodically I attempt to tighten them, they are completely secure.  They don't bother her in her sleep at all, and they are really attractive.

UPDATED JULY, 2013:
My daughter JUST LOST one of these earrings for the first time!!  Buying another pair now ... Amazing.