I use a variety of training methods with my dogs.
However, until a dog is at least 9 months old, I use a regular flat collar and all positive reinforcement. Since this has come up before here and on other boards, I want to clarify: I define positive motivation as giving the dog something that he/she desires in order to increase the likelihood of a behavior occurring. This could be food, play time, tug, etc.
I have used the clicker with my most recent dog, but find that I like food much more (especially with his food motivation).
Around 9 months-1 year of age, I start adding positive punishment (or compulsion). Again, to clarify: I define positive punishment (or compulsion) as giving the dog something he/she does not like in order to decrease the likelihood of a behavior. My choice for compulsion at this age is a prong collar. Before using one, I place it around my dog's neck, and allow it to just wear it around the house for 1-2 weeks. At this point, my dog knows the basic commands, but needs to be shown that it's NOT okay to NOT do the command. There are people who use choke chains. I will not use them as there is evidence that they can cause esophogeal damage due to uneven distribution of tightness around the dog's neck.
I teach with motivation, proof with compulsion and motivation. I never stop using positive reinforcement with my dogs. If they do something they shouldn't, I pop them using the prong collar. If they do something right, they get rewarded for it.
I recommend, though, learning to use a prong collar under an experience trainer (as they are often not used the right way and are ineffective as a training tool as a result...and then get a bad reputation).
I try to stick with a prong collar, but owning working dogs with very high drive has made an e-collar a necessity. I don't like to put my dogs in e-collars until they understand what a correction is. Again, with this tool, I let my dogs wear them for 1-2 weeks (during the day only) before using them. Then, I train them WITH the prong collar (the electric correction comes with a pop on the prong for several days before using the electric on it's own). I use the electric to proof things during distance work (long downs, change of positions, and during bitework for the out, etc).
My dogs are working dogs and compete in PSA. I never actually practice the off-leash work. Even with the dog I'm working for the Level 3's, who will not even wear a collar when we compete....He always wears his prong (and leash connected to it) and his e-collar. I always do his obedience with his prong collar and leash. Why? Because I don't want him to be able to get away with anything, ever. I have to be ready to correct immediately. The goal is that when trial day comes around, the dog is so used to being corrected that he is less likely to step out of line (so to speak)....
Again, I will add that an e-collar should be used under the supervision of an experienced trainer.
Hope this helps. It's just my opinion, but have found that it works (and by the way, with "pet" dogs, my boyfriend will typically put them in a prong collar around 5-6 months of age as opposed to older for a working dog).