Can all countries have the same currency and same exchange rates?

No way, that can ever happen.. IF all countriess have got the same currency and same exchange values, the whole financial world will definitely be in a mess.. haha =D AND there will be no more forex, for investors to be earning or lossing money.. In short, there will be a short of source of income for the world.. haha =D ANd if all countries have same curreny, it means that your country might even need to fork out money to help out greece, who's facing bankrupcy!! Would u want that?? haha

On the old days, Dollar and Philippine Peso have the same currency or value, I dont think it will ever reach that time now because of crisis everywhere.