My husband & I have two small puppies, so as you can imagine, we take them on walks quite a lot, so we needed a couple good leads that would not only give us control, but also give the dogs some freedom to roam while on their walks.
We found these retractable leads at Petsmart while buying pet food one day and we immedietely decided that these were what we needed. They come in different colors and sizes and they are very easy to use. You just attach the clip to the dogs collar or harness and the hold the handle and while you are walking your dog, the dog can run as far as the lead will go or until you depress the button on top to stop the lead from expanding any further. At that point, even if the dog doesn't come back, until you release that button, the lead will retract back in to the handle so that you can minimize the distance that you are from your dog.