Well, the Central Bank mention is kind of funny. We don't have a true central bank.
We have the Federal Reserve, but that's a consortium of banking executives that are given governmental powers.
The last time we had a true central bank was the Second Bank of the U.S. Andrew Jackson disbanded this.
Some countries have central banks, but most modern currency is heavily tied to trade policies and the currency exchange market itself.
The funny thing is... there's a strong argument for creating a Third Bank of the U.S., since the Federal Reserve is an institution that seems to have made several moves that have endangered the value of our currency (mostly with respect to vastly increasing the money supply and maintaining unrealistic interest rates).
Theoretically, a third central bank would stabilize monetary policy, especially in contingency with a commodity based currency. Granted, it's doubtful we're moving away from a Federal Reserve anytime soon.