Buying speaker and amps from Canada to the US.Tax?

I have had a few items shipped to me from Canada. If you use UPS, your asking to be charged. If its a light item use Canada Post as Sean mentioned. If its heavy, use Fed Ex economy international air, its quite reasonable. From what I can tell, the trick is to ensure that the person shipping the item to you fills out the duty papers properly. I was told to use terms such as "For personal use Only". The stereo shop also taped to the box a page of the brochure of the speakers that showed the speakers and also said they were make in Canada. Even then, one of the speaker boxes was opened and inspected, but no duty/other charged.