Now, some alternate cryptocurrencies have that potential. I am not that blind Bitcoin believer, so I expect one day it might be replaced with some other cryptocurrency that will evolve from it. That is entirely possible and it would be naive to think that Bitcoin is not only the first, but also the last popular cryptocurrency the world will use. Things that are first, rarely turn out being the last in this world.
+1
By using scrypt as their hasing algorithm, albeit choosing odd parameters for it, LTC really did some innovation there. I'm not sure about PPC, I dont buy into that whole proof of stake thing.
Personally, i'd like to see a cryptocurrency introducing a "tax" on coin hoarding, to keep the money flowing thus driving the economy