I too was having this dillemma! My wedding colors are purple and turqoise, and after searching for BM dresses the ones that I liked ended up being in a bright, rich purple. Originally we decided the boys would wear khaki linen pants and white shirts but I wanted to ensure that my FI was different from the rest. After reading a ton of posts from other brides and examining pics online, I came accross this article:
http://www.bridalguide.com/photo-of-the-day/bliss-events-contrasting-colors After seeing this, we decided to put the GM in turqoiuse shirts and the groom in white. I think it could make for some great photos, and since its a destination wedding I hope we can pull it off!