The first Euro coins are being minted and 12 out of the 15 EU nations are going to replace their money with these on Jan 1, 2002.
Remarkably, they have only 2 months to circulate both their own currencies and the euros. So by the end of February, 12 world currencies are going to disappear.
I know the UK pound is going to remain but I don't know who the other naysayers are. The French franc, the German mark, the Italian lire, the Spanish peseto, all are going the way of the dodo bird.
The Brits might be out because the pound has stronger backing, but they might also be gun-shy because it was only a few decades ago that they went through a currency change - decimalization. They lost the shiling and sixpence notes and their "penny" changed in value which was fairly traumatic. Can you image a US cent being suddenly worth something other than a cent? Any confusion like that breeds temporary inflation as there is confusion over the worth of money.
In the long run I would expect that the sudden ability to trade without an exchange rate will have the opposite effect on Europe. No exchange rate at all, they will have an understanding of the worth of the euro that crosses borders.