I took my two sisters (who are my bridesmaids) and my aunt. My mother had to work that day so she was unable to go. Needless to say, they were very helpful and I found the dress of my dreams! I know some books and websites say not to bring too large of an entourage because differing opinions can cause a disaster. I think you just have to be really selective about who you want to accompany you - take the people who are tactful and honest. I honestly think my last visit was successful because my mother wasn't there. She is very opinionated and isn't very open minded which made our first trip shopping very difficult.
But anyway, that's my two cents. Good luck in finding your dress! I'm sure it will be beautiful!