What are the best places to shop for bridesmaids dresses?

My best friend is getting married and I need to get a dress. We are not wearing matching dresses but they have to be the same color. I have already checked out JCrew, Banana Republic and Ann Taylor. Any other suggestions? I don’t want a dress made of typical bridesmaid material (taffeta, etc) rather something I can wear to other weddings, parties, etc. Any ideas?