So here is a rough guide to each style:
The Halter neckline This fastens at the back of the neck and dives quite low in front. This is style suits taller brides with broader shoulders and is generally less flattering for those with a larger bust
Beteau or other wise known as the Boatneck
From shoulder to shoulder this style is slightly curved and sits on the collarbone. Great for those brides with a larger bust who wishes to minimize attention to the bust area.
Square neck - Although it offers a rather open neckline it does not plunge too far into the bustline. Another great option for those brides with a larger bust.
High neck - speaks for itself
Spagetti Straps - Especially great for those who want that little added security.
Off the Shoulder - This style sits below the shoulders and has little sleeves that cover part of the upper arms. Always make sure you test this style out as movement can be a little restrictive.
Asymetrical - With a strap over one shoulder this is a great option for a less formal wedding. Best suited for the brides with a delicate collarbone
Another example of a slightly shorter dress with a Bateau neckline
Sweetheart - A popular choice for brides, certainly a great option for a bride who wants to modestly accentuate her cleavage
Another example of a beautiful dress with square neck