I prefer Nike and Adidas, but Converse must get run for street sneakers (Purcell/All Star). While I prefer Adidas for streetwear, I do see myself pulled to Nike retro styles. It seems that they put more technology into their retro sneakers (love Air Zoom Trainer right now) whereas Adidas puts little in. This makes a difference if you are walking a lot. As to the running shoes, from the diehard runners (think those who subscribe to Runner's World), I would bet New Balance, Brooks, and Asics would be mentioned most for running. These brands would probably be mentioned because they focus on running.