I use my road bike for commuting. Its a 1996 Cannondale with 105/Ultegra mix that I built myself at the beginning of this year. My commute is 5 miles one way and I don't have any panniers, I just carry everything in my backpack which is: a change of clothes, lunch, two snacks (usually a fruit and smoothie in a flask) and thats it. I don't need to carry any documents to work. Here is a picture: