I just returned from a quick visit to Canada and was somewhat surprised to see the price differences, or rather, similarities. I went to all the major retailers just for a peak, and I was shocked to see, that GST aside, Hong Kong and even the mainland are almost identical to prices in Canada now, at least for computers. The days of cheaper electronics over here are over I think. However it could just be on computer goods only. With the GST it is probably slightly higher, but who knows, Hong Kong may have their own GST soon enough... But I helped my brother in law buy an Acer laptop back home, and recently helped various friends here buy the same machines. I also bought a multi-function printer back home for my mom, liked it so much I bought another one here, once again, almost identical in price. One thing I would consider however is warranty. A lot of companies I have seen now are offering very nice warranties while you are in Hong Kong or China, 3 years on a decent policy. However, if you leave China, then it becomes a 1 year limited travellers warranty right off the top. I can't say if it is the same for Canada, but I suspect you would have a harder time getting repairs or support here for something bought there. Getting warranty help can be a pain in the butt even in the place you originally bought the machine, with all appropriate reciepts, the day after you bought it, as it is burning on your desk...... But I digress...
So if you plan on staying in Hong Kong for 3 years or more, I would suggest you probably buy your machine in Hong Kong, then you don't even need to replace the power cables. If you are coming for 1 year or less, I would shop Canuck.
Remember when all us Canucks would go shopping in the states because everything was cheaper? People would talk about the crazy deals on electronics in Hong Kong?
Those days I think are over.