Ooh! Important tip to travellers of the actual, physical world: when you shop in Canada, regardless of the currency you use, you will get your change in Canadian funds!!! No, our stores don't keep a stash of Euros, Pounds or American dollars on hand!
This may sound strange (or at least like one of those "Well, duh!" moments), but I actually waited on an American tourist today who was surprised to get Canadian change in return for her payment in American funds. Hel-lo?!?!
To arm yourself with knowledge, check out the current bank exchange rates and the currency calculator at X-Rates. Actually, it's kind of fun! Tailor-made for insomniacs, world travellers, soul-less business types and the obsessively compulsive alike.