Just to share my experience ( sorry! this shall be the last word I should say...) I went to US last summer in Cincinnati, and visted a department store called " Best Buy" quite similar to Harvey Norman here, I intended to buy Canon 40D kit 28~135MM, the price was USD1299, but with only warranty within US and Canada, comaparatively still cheaper here ( as on last year price), but owing to the limited warranty condition, i decided not to take the risk! When i returned to Singapore, I visited Amazon.com, it was offered at USD1199 ( approx SD1800), so I ordered one and send to my HQ in Cincinnati and asked my colleague to carry back to Singapore, it was a grey market product, ie it carry a limited warranty in US & Canada but not beyond that region and also the packaging was in white box without the typical Canon glossy box, other than that it was just like ordinally puchased from AD...
The catch is :if you order from outside Singapore, any thing above SD300, you are subjected to 7% GST and rather expensive courier charge and also very poor credit card rate...so think twice before you order, for my case I was freed from the above problem except the credit card's poor rate.
To my perception, it is still cheaper to buy from outside SIngapore, for my case i reckon i could save approx. SD 500 ~ SD 600..;p