One can get a french manicure done with a white or baby pink nail polish only on the nails cap and transparent or base coat on the rest of the nail. One can also use one coat of silver nail polish or baby blue nail polish sandwhiched between two base coats.
If you're attending a formal event I would go with a classic french manicure look. You could try to spice it up by adding blue or silver diamond studs to certain fingers but I wouldn't go with an actual color on your nails. A nice blue would look good on your toe nails.
Depending on your style, I would go with a french manicure, or a natural nudey pink color. This way, your nails won't clash or take away from your beautiful formal dress, while still looking pretty and polished.