We always use non-retractable, usually leather leads because they last longer and don't give you rope burn . Rectractable doesn't really give you any control with big dogs. I have used the retractable when we go to the snow, or hiking or out where there aren't many people or dogs.

also.. I have a pet peeve. I *hate* it when people are walking their dogs on retractable leashes, and the dogs come running across the street at us (usually it freaks Gonzo out) and the owners are either struggling to stop the leash or just not paying attention happens to us a lot.