Jed, I am in the US earning US dollars. When I go back to Canada for a visit a US dollar goes a long way. On the other hand, the relative strength of the US dollar has protected a lot of Canadian jobs during NAFTA. I can't imagine what a common currency would do for this continent, but I doubt if it would be good for Canada.

Skipjack8 Oil exporters / Oil importers seem to fight quite a bit within larger economies. Texas is a at political odds with New York State as Alberta is with Ontario, as Scotland is with England. Seems like the consuming States/Provinces/nations always seem to have more clout and get their way. I don't think that would change with European union. Energy policy would still be set to favor consumers rather than producers and cities rather than regions where the resource resides.

Commonwealth, what Commonwealth, It hasn't been a significant trading block in a long time. In the long run it makes more sense for Australia and India to trade is Asia, For the UK to trade with Europe and for Canada to trade within America.