Strong and a 3/8"-1/2" wide leash will be more than sufficient. If
you do any obedience training, the leash must be six feet long, but
the nylon leashes are much cheaper than the leather ones, be
careful with them as they can give you a bad case of "rope-burn" if
strong and a 3/8"-1/2" wide leash will be more than sufficient. If
you do any obedience training, the leash must be six feet long, but  
the dog decides to take off when you are not paying attention!
Nylon is fairly slippery and doesn't allow for a good grip. For
walking in the wide-open spaces or exercising your dog, consider
the purchase of a Flex-lead. This is a wonderful product that allows
the dog to move out either 16' or 26' away from you on a
retractable lead. With this one, you can truly just stand in one spot
and let the dog do all the running.....very handy when trying to get
the dog to eliminate!

My favorite crates are the metal ones made by Midwest called Life
stages. It has a double door and is perfect for crate training.  
Proper adult crate dimensions are *about* 16"W x 22"L x 24"H. But
what's good about this crate is the puppy can use this crate from
puppy hood to adulthood.