My bike to work clothes are jeans and a T-shirt, or sometimes shorts and a t-shirt in the summer. When it's cold, I wear sweats. If it rains, a Spiewak set. I wear a helmet for two reasons: 1) PAX gate guards will not let you through without one and 2) If I get KIA without it, that'll be what's blamed and not ****ty driving.
Oh, also it keeps the cicada's from thwacking me in the forehead, I guess.
M.