I just looked at a random new release DVD - "We're The Millers" - in iTunes in Australia (the only one of the above options that seems available to us downunder) and the buy price (HD movie) of $29.99 is more expensive than the physical disc from a local retailer: http://www.jbhifionline.com.au/dvd/newreleasedvd.htm ($24.98)

$6.99 rent price is substantially cheaper if you only want to watch it once though I guess.

Not sure if GP meant "new release movie" as in still in cinemas as opposed to "new release DVD"