In NYC its considered weird to wear anything but black to a wedding! 
(ok not really, women do occasionally wear colors and they aren't seen as weird, but black is definitely the most popular dress color for formal events 'round here.)
Amen. There is black and there is black. The classic LBD with a bit of color in the jewelry or accessories is just fine in NYC. It's seen as formal and a way of drawing attention to the bride.
The problem of wearing black to a wedding is if you dress like a traditional Mediterranean widow. That would be seen as a sign that you did not approve of the marriage.
That is exactly what happened at my wedding. A relative wore a black dress and a large black hat to my wedding. She is someone who I believe did not approve of our marriage, and I felt it was rude. Had she been someone who I knew wished us well, I would have felt differently. Festive accessories should be worn with anything black to alleviate the appearance of mourning, is my opinion.
