I can see that the trend-line is bearish so I will short in a position between 50% and 63% following a Fibonacci retracement. The market is unpredictable so my short will start more closely at 63% than 50% at 666$.
Because all DoS attacks to exchangers the market is acting bearish so my target is at the last resistance level at 632$. I don't think that this level will be broken on Bitstamp because they managed well the situation. Once the issue will be repaired the market will rise.