Great thread!
I'm in the fortunate position of being able to choose the distance of my commute. The short'n'sneaky way is only 3.5 km (~2 miles) which allows for not wearing anything more cycling specific than helmet and the velcro thing round my ankle. Other routes range from 7 km to 13 km to wherever I choose to go that day. Gear is modified accordingly. I don't use fenders, though. I have a lightweight rain jacket in my bag if rain surprises me, and if I'm prepared I wear the pants as well. The short route is cirkus 10 minutes so it's not too bad.
Cool thing is, I use my bike (kona jake) for everything: commuting, weekend rides, café racing, shopping -- just as I did as a kid.