I wear whatever as far as clothing but I always wear a helmet, cycling gloves, and those little reflective things that keep my pants out of the chain.
That being said, almost all of my jeans have this sort of perma stain on the bottom from my chains, anyway.
In the summer its whatever shorts and t-shirt don't smell as bad as the rest. I don't dress up to ride, i dont own a car so when i want to go someplace it's bike or walk.