For our little guy (65lb lab mix mutt) we have the plastic coated cable. Have had the same one for about 3 coming up on 4 years.
Most of the time we don't even hook it to him because he just lays at my wife's feet. He is a big baby and freaks out when he can't see her.
For walking around the park just a normal leash. He's a good boy doesn't pay any attention to the other dogs that are barking or walking. Guess we lucked out in that department as I wouldn't bring him if he barked at everyone and everything. The only time he makes noise is when his kids come back to the RV and he gets all excited.