I don't use a stop loss when I trade. Since I made this decision I have been profitable. I read a lot on here and other forums where traders talk about not using a stop loss as a crime to trading, it's just unproductive to be so opinionated. Using them has as much merit as not, it depends entirely on your overall strategy, your experience of the currencies you're trading and a million other things. I personally developed a system without them as it gave me a psychological edge and comfort when trading, this added confidence has helped me grow profitable. Just because I don't use a stop loss doesn't mean I would just let my positions run into the ground when they go against me, I reduce position sizes, hedge and many other things. It is not simply whether or not you use stop losses that will make you a good trader it is everything else you do to support that decision. If a new trader went into the market blind, paid no attention to fundamentals or statistics and just opened a position long or short, a complete punt, I would absolutely advocate using a stop loss, if however you are trading that way you may as well head to a roulette table.
Good luck to everyone using them or not, if it works for you and makes you money great!