I think $50 is a good guess at it's bottom.  I'd be really surprised if it went lower.  The people saying $10 or less need to stay off the silk road (ie stop smoking crack).  There's at least some non-speculative demand that will keep the price somewhere above that.  Also, as the price gets lower, the chances of there being a rally becomes more and more likely as speculators and hardcore believers take advantage of a good buying opportunity.