[PaulAJ]

Bitcoin prices will be no more stable than conventional currencies, because money supply is a rate (BTC / sec) rather than a total volume (BTC). As commerce using BTC slows down so the money supply decreases. As commerce speeds up so the money supply increases. The exact relationship between the money supply and inflation complicated and somewhat controversial (see Wikipedia for more info), but there is no doubt that if, for instance, all the people currently holding Bitcoins as an investment were to sell them then the value of Bitcoins would drop, because the money supply would increase.