This is one I use. It's short so I have more control over Sky. She is kept on a lead in public areas and let off on beaches/fields/in woods.

Sky has this collar in black

Choke chains should not be used by anyone who doesn't know how to use them. You may think that if the dog is choking, it's doing its job - this is not the case. You are harming your dog.
If you insist on using a choke chain please learn how to use it.
<http://www.ehow.com/how_2059928_use-choke-chain-dog.html

This is a half check. Only a small portion of the collar is actually chain. It is very good for walking and training.

This is a prong collar. I am totally against using this on a dog, but some people do. It's usually seen on Dobermans.

This is a halti. It is not a muzzle. A muzzle is used to stop a dog from biting someone. A halti is used for training a dog that pulls when it walks. You need very little correction when using a halti.

This is a harness. I used a harness to train Sky how to walk and am now pleased to say she does not use a harness anymore. I walk her on her collar and we have no problems (unless she spots a bird, she hates birds).