Hiya, thanks for the link to my
US$ Credit Card for Canadians article.
I just wanted to chime in with another advantage of a US$ card:
If you purchase an item in US$ with your CAD$ Credit card and then return the item, they still charge you the currency exchange commissions, perhaps even both ways.
With the US$ Credit card, since the purchase and refund are in the same currency, you're no worse off than where you started when you do a return/refund.
If you qualify for free
TD Select Service, their US$ TD Visa annual fee is waived, and you get a free US$ Account with preferred exchange rates, but you need to keep $5k in your account at all times to get the fees waived. Alas, I don't have the free TD Select Service account
PS: Nice site, I'll be sure to post here