This may be a little off topic, but that's why I'm posting it here. I'm Canadian and a Mac user and just before Christmas I needed to get my G5 serviced with a new power supply. I was down for about 2 weeks, but I had just bought an Intel iMac for home and was able to transfer all my photography work to it for the duration. All my work that is except for my accounting software. Turns out that the product I was using is no longer supported in Canada on Mac computers. I was running it in Classic mode under OS-9, on my G5, but since the new Intel Macs won't boot under OS-9, I was out of luck.
So I started looking for new Canadian Accounting software that would run under OS-X. I found it in New Zealand. It's called MoneyWorks and handles GST/PST (even HST) perfectly. Most of the other popular accounting software companies have abondoned Canadian Mac users. I downloaded the trial, ran it for a few weeks and was impressed. I bought the middle package, Express, and have been using it ever since.
In fact, I was so impressed that I've become a reseller for the software. I know this is a little self-promotion, but if you are Canadian and running your life on a Mac, I'm sure you know the frustration I felt trying to replace my aging accounting software with something up to date and reliable. So I'm just offering out there to anyone who's interested and if you would like more information or have some questions, just let me know. The website is MGPacc
Hope this helps.