I suppose you ask for the growth in value and not in the growth in number
I doubt it is Litecoin, because it already had some very good weeks.
People might want to believe that a coin that has not yet gained so much value might be more interesting to invest the money in.
Primecoin is interesting and fascinating because of its imaginative PoW. But I bet it won't be one of the best growing cryptocoins.
I think Peercoin (PPC) does have one of the greatest potentials. It is one of the coins that has not yet been recognized by the mass, although it offers something important and new, which is it introduced
"Proof of Stake" (PoS).
The number of PPC is technically unlimited, but there might be less PPC in total than e.g. LTC, because the PoW reward of PPC is not a function of block height, but of difficulty. So the more hash rate in the network is doing PoW, the lower the reward (each 16-fold of difficulty halves the reward) per block will be.
Transaction fees are not earned by miners but destroyed.
And the PoS reward is only roughly 1% per year (which shall long-term balance the destroyed fees).
That will lead to a more or less stable amount of Peercoins which is way under the technical maximum number and not very much above the current number of roughly 20 million PPC.
Short-term the PPC network might profit from the legions of SHA256 miners that are bought for BTC mining once their owners recognize that mining PPC with them can be more pofitable. That draws attention to PPC while the PoW miners will earn less PPC as more hash rate is in the PoW process.
Long-term PPC has a good chance to endure, because the more the network transitions to PoS (there already roughly 10 times as many PoS blocks than PoW blocks:
http://ppc.cryptocoinexplorer.com/chain/PPCoin?count=50&hi=84842) the less dependent on PoW it is.
That makes it easier to sustain the network security, because a drop in network hash rate doesn't make it easier to perform a > 50% attack if the security is mainly based on PoS.
And even if a PoS attack is possible, it does not make much sense. It is more expensive than a "PoW > 50% attack" and the coins would be rendered worthless (or at least much less valuable) in case of success (successfully having minted a PoS block freezes the PPC for 520 blocks before they can be spent; until you get them to an exchange no one will want to buy them...)
Novacoin could basically have the same chance long-term, but can not profit from SHA256 miners short-term by getting that kind of attraction.
So I guesstimate that the future will be great for Peercoin. I hope this future starts 2014
I don't take pure copy-cat cryptocoins very serious, but who knows...
...and who knows what improvements follow?
Some improvements by new cryptocoins can't simply be integrated to Bitcoin. Those cryptocoins might have the highest potential.
Poll
