The only thing that could beat BlackCoin, imho, is a currency that paid interest based on volume transacted, using some algorithm to determine which transactions were truly long-running investments and rewarding those with a higher long-term interest rate (i.e., you start by earning A% per coin per 8 hours, but after a X amount of time determined by the liquidity of the market you top out at B%, some adjustable rate of interest based on an algorithm that determines how tight the money supply should be; holding coins longer than that, it starts to go back down). In the meantime, having a very low fixed rate of interest effectively allows BC to be a carry trade instrument for Mint and other high-yield coins, should prices stabilize after a couple of years. And whatever happens to the other coins, it can remain so.
A coin with a rate of interest adjusted by the transaction volume is a very nice idea. Maybe, we'll see one eventually. A currency based on the equation of exchange:http://en.wikipedia.org/wiki/Equation_of_exchange
with an interest rate algorithm designed to keep prices (roughly) constant would be very appealing.
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