Hi JumpRat,
Here's the place you want to go:
E-Compuvision
I bought some arctic silver from there a while back, and in all honesty I've never seen a better ordering process. They give you four different options for shipping, tell you exactly what it'll cost, they have reasonable prices, and a very navigable(sp?) page.
They're my first choice for Canadian cooling supplies.
And, in a VERY distant second, I suppose you could try
Bigfoot, they're pretty expensive though. If you live in or around Toronto, you can save on shipping from either place if you go pick it up.