Sorry for the stuttering--I was excited. Anyway, it seems like there's some direct correlation between a pony's name and his/her Cutie Mark, or at least its appearance.
Quick clarification on the example of Rarity:
What I meant here is that despite her parents being fashion-inept, Rarity's talent is fashion. However, her Cutie Mark is not necessary related to fashion, but rather a love of diamonds, which are rare. A rare gem, such as diamonds, is a reflection of the name she was given rather than the talent she possesses. So to some extent, it seems a pony's name plays an important role in their reception of a Cutie Mark.