I think duties are proctectionist rubbish. Duties on a laptop? Ridiculous. It's not like there's a Canadian laptop manufacturing industry we're protecting.

Sales taxes however, are a different matter. If you go over the line to buy a laptop to my mind it's not unreasonable that you should have to pay sales taxes when you cross back into Canada.

If you don't want to pay taxes stay over the line for two sleeps or buy it on Craigslist.