Bitcoins current price is not in line with its utility value at this point in time, people are getting greedy looking for a get rich quick scheme. Bitcoin was not designed so we could all be millionaires, but designed as a decentralized currency where fees are an order of magnitude smaller than traditional payment methods as well as the inability for governments to devalue your money through hyperinflation.
People have begun hoarding their bitcoins rather than spending them and without active commerce bitcoins intrinsic value is nothing.
I can't tell for sure when the crash will happen, but I feel that we are nearing critical mass. It may reach $250-$300/BTC before it happens, however I feel it is inevitable.
I for one have liquidated my holdings.
More people are interested in Bitcoin therefore crash.
QED
People are interested in bitcoins to make a quick buck and not for its inherent value therefore crash.