AFAIK, the only model that has some claim to statistical legitimacy is the log-Brownian (or geometric-Brownian) model, which gives a very broad probability distribution, having 50% chance above today's price, 50% below, for any future date.
50% chance above and 50% below, for any future date, are you serious ?
Yes. What will be the price on Nov 17, 2014, at 17:23:11 UTC? The log-Brownian model say that it will be more than 487.15 USD with 50% probability, less than that with 50% probability. (OK, there is some probability that it will be EXACTLY 487.15 USD,but it is very small.)