Tee hee...that is exactly what I wanted to ask someone when I was going to my first conference...it is so important for a girl, isn't it? From what I can gather, it depends on what conference it is, and where it is held...some are all suits and ties, some a bit more everyday wear...can't be more specific sorry. If you are presenting, I would put effort in to look professional - when I presented, my supervisor kept asking me what I planned on wearing, so he could approve/advise...he even started advising about ironing techniques, but suspect that was a joke!