This is an interesting thread - it appears many of your more common candlesticks are something many traders here use. Some use them mainly (like myself) and others use them in conjunction with other items (like Soul with Pivots).
I think there's an important thing to note though - MANY traders use candlesticks, in some way, shape or form. There are purists like myself that are hunting for candles first and others use candles for additional confirmation. I think that's why you see candles work well at times - when all of 'us' are on board at the same time, it's easy to see why candles can be so powerful at times. In the end, candlesticks and anything else can be a self-fulfilling prophecy if enough people are using them at the same time, right?
I think it's prudent of all traders to at least be aware of candlesticks and the story that is being told between the fight of the bulls and bears. Every candle print is saying something and candles can provide a quick and easy way to see who won the fight or if it was a draw. Being able to see the story being told in front of you can help your trading, even if just used as a confirmation for some other methodology.