I honestly feel that the rise of silk road was a sign of bitcoins success.  If people/addicts were willing to trade btc for their high of choice, it is a sign that bitcoin works as a currency.  Even if the seller then converted to USD, bitcoin filled one of its primary purposes.  It was used as a cheap, decentralized means of exchange out of the control of a government or financial entity.  Hopefully in the future, we can reach a point where there is some stability in the price of bitcoin vs major fiat currencies, and people will feel more comfortable storing value as bitcoins just like they do with any other store of value (precious metals, currencies, equities).