Acer AL2423WD at Harris Technology $461.50
Harris have this monitor out at '10%' off for buying it online. Whether or not thats entirely true who knows. But the online price is $530. Acer have a $49 mail in rebate on it out at the moment as well to make this better and then you get 4.05% cashback through here.
Delivery to Perth as an example would normally cost $31 or so but Harris being Harris they have a pick up joint in each state, so you can cut out the shipping cost by picking it up while at the same time getting the online discount.
So the price figures out as $530 - $19.51 (cashback) - $49 (mail in rebate) to a total of $461.50 thats better than I can find it anywhere else.