@wavy58 - My workplace is also somewhat informal. Most of the women dress to impress each other anyway! I think that one thing we all look forward to each day is seeing what everyone will be wearing.
I love the look of sleeveless collar dresses. They also have the long point collar that is quite loose. That way, even though I am wearing a dress, I still feel relaxed and comfortable.
I deal with the public a lot, and I believe clothing has a subtle effect on how people treat you or perceive you. Collar dresses with loose collars make me seem respectable yet open and approachable.