Odd that no one has mentioned the side effects - a high C$ hurts Canadian manufacturers who sell to the US, because their goods are much more expensive in US$.
Conversely, a low US$ helps US exporters, and might someday help dent the US trade deficit. One does wonder what the Japanese and Chinese, as holders of hundreds of billions of US$ debt, think of Bernanke's rate cut and the incredible shrinking dollar.
Well, yes and no. A lot of what Canada ships across the border are necessities. While the appreciating Canadian dollar might make things more expensive, it's probably more expensive to import it from overseas. To a degree, the US and Canada are captive markets of each other.
What does the US export exactly? Much of what the US imports from China simply isn't made in the US anymore so I doubt the US will see a significant change in the trade deficit.