The ideal lead for your dog depends on what type of walking you do with him. If you need to keep him safe in street areas or densely populated areas, a webbing lead of 2m long, with a clip to fasten to the collar or harness, is a great choice.
This length of lead is longer than most of the standard leads, and some brands have two rings to adjust the length to the full 2m or to 1.5m, depending on the activity.
If you are going on a sniff walk in a safe park or open land area, a webbing long-line (5m or 10m) will give your dog a wider radius to sniff, and reduce tight leads as your dog navigates around interesting smells.
Stick with the webbing, as it is soft on the hands and will not hurt the dog should the lead accidentally become entangled in his legs.