..see you at $100...
The last big bubble lifted the price from ~120$ in early Oct/2013 to ~800$ in Jan/2014. The fall from ~800$ in Jan/2014 to the present ~350$ can only be due to the undoing of that bubble (and to the undoing of the May/2014 "pseudo-bubble").
I cannot see any plausible explanation for the Oct-Nov/2013 bubble other than the opening of the mainland Chinese market. The undoing of that bubble then must be due to the loss of that market. According to a few articles, the Chinese bitcoin market consists mainly of amateur and semi-professional speculators who, lacking access to the stock market, were used to day-trading other bizarre commodities.
So, if those traders pull completely out of the market, the May/2014 pseudo-bubble is completely undone, and no new market opens, the price should eventually go back to ~120$.
Draw a straight line on the Bitstamp price chart, in log scale, from the prices at Jan/2014 (~800$) and at May 19, 2014 (~400$). Extrapolation of that line suggests that the price (minus the May pseudo-bubble) will reach ~120$ by the end of the year.
I suspect that the Chinese were responsible also for the Jan-Apr/2013 bubble, that lifted the price from ~12$ to ~120$. Specifically, the start of that bubble seems to coincide with the hiring of Bobby Lee by BTC-China in Shanghai. In that case, if that market closes too, so that the Jan-Apr/2013 bubble gets undone, the price could go down again to 10--20$.
Needless to say, these extrapolations will be moot if another market opens (COIN? Argentina? Africa?).
i know: a new market is in order!