( Photograph above from Lux Photographics.)
I think the right vintage brooch can really take a beautiful dress and make it stunning. It's a way to make the dress uniquely yours and is an accessory that is highly overlooked by brides. It can be a wonderful way to get your "something old" in there and even incorporate an heirloom piece from a grandmother or other family member. Brooches are beautiful as part of a sash detail (like above), centered under the bust line or even off-center at lapel height.
Here are a few of my favorites from etsy:
This one is so gorgeous and even feels a little modern. It measures 2.5" across and is studded with rhinestones. You can find it at Concrete Vintage.
For a Scottish bride or groom this one would be so special. I love how rugged and organic this one is. It would juxtapose so beautifully with an ultra feminine gown and a bouquet with thistle details. You can find it at Grace, Art and Antiques.
I'm a huge fan of mixed media jewelry! And this is such a dear little thing! At two inches in diameter it's pretty sizable, but the design is so soft. At $6 this piece from Koup is a steal!