I ride in street clothes. When it's cold I put on some leg warmers underneath my jeans, and when it's raining I put on a cheap pair of rainproof pants over them. I also have a light rain- and windproof jacket I use. I just keep the speed down so I'm not too sweaty when I arrive.
I used to ride clipless but reverted to platforms recently. The clipless pedals started to feel like they constrained my freedom. I'm sure it's just a sentiment, but sentiments are important when cycling.
My commute is about 10 miles.