I carry my clothes in a kayaker's dry bag... not so chic, I would guess. Of course the very first day I rode to work it poured rain so hard it was raining up, down and sideways.... my messenger bag didn't stand a chance and did leak (don't think it has since). Since I transport my camera back and forth I'd purchased some dry bags already - not willing to take a chance with it. I was happy and my clothes were dry when I got there.
I actually like wearing skirts at work, they take up much less space in my bag than pants, but I have a fairly active job, so I usually save the skirts for days I know I'll be mostly at my desk. I leave my shoes in my locker and I shower at work. I don't ever blow dry my hair (I have naturally curly/dry hair so not unless I'm going for the bozo the clown afro look....) and I don't wear makeup, so getting ready is pretty easy.