Hmmmm. Normally I would say the drop one, but it's got alot going on. Pretty and all, but I think it's too much with your dress. And I don't think it should hang below the beginning of your dress, or get caught in cleavage. If you like the idea of a drop necklace, I think going a simpler route would be better. A simple elegant chain, with one teardrop crystal, or something like that.
Personally, I am not a fan of the rounded necklaces, cuz I think they tend to look flat or something. The pendants give definition to the neck and chest area.
I chose not to wear a necklace for my wedding, cuz I didn't think I needed it in my low v-neck dress. Looking back at pictures, I really wished I had a necklace on. Not sure really why, but then I did wear one for the AHR and I think it looked so much better.
Ohhhh! I just thought of something that could be perfect! Well, the style anyway, not so much the color. but I just saved this etsy item to my favorites, cuz I really liked it for a dress that I am wearing to a wedding next month. Something with this simple style would be nice with your neckline.
Etsy :: opheliax :: Golden Shadow Swarovski Wrap Necklace
Actually looking at it again, it's kinda big as well. But I like the general style of this better for your dress....