What about buying from the online Apple Store (http://store.apple.com/nz)? How do the prices compare then?
To give you an idea of the markup, a 15" MacBook Pro 2.66Ghz costs US$2199 on the American Apple site. If it were sold for the same price in New Zealand it would cost NZ$2870. It actually retails for NZ$3799 (nearly NZ$1000 more).
$2870.00 * 1.15 = $3300.50 $3300.50 < $3799
(We have a 15% sales tax that also applies to items ordered from overseas over a certain threshold)