Bearing in mind that while you are saying your vows, most of your guests are going to be looking at your back, why not go to town with a statement back detail?
This could be a short cape with delicate beading, a complete lace back, a cut-out, beading all the way down or even a train with lace panelling.
If you don’t want to shock your celebrant (or family) by showing too much flesh up front, then this is a great way to add a wow factor to what appears to be a more demure dress, plus, it’s a nice surprise for your groom to see as he won’t know what you’re hiding as you walk towards him!