If you're a student, or you know a Student you can purchase a student membership to the apple developers connection for A$ 119.00 (GST inclusive):
http://store.apple.com/au/browse/adc
What most people dont know is that this membership entitles you to 1 heavily discounted life time purchase from the developers store:
http://store.apple.com/au_epp_55827
MacBook Pro, 15-inch, 2.8GHz, 4GB, 120GB SSD
-SuperDrive 8x (DVD±R DL/DVD±RW/CD-RW)
-2.8GHz Intel Core 2 Duo
-128GB Solid State Drive
-Accessory Kits
-Keyboard & User's Guide
-4GB 1066MHz DDR3 SDRAM - 2x2GB
A$ 5,279.00 with GST (through normal apple store)
A$ 4,222.90 with GST (through developers connection)
= A$ 1056 Discount! (Thats without the 3% Buckscoop Cashback!)
Personally I would go the 320GB Serial ATA @ 7200 [Subtract A$ 575.30]
NOTE:
You can try printing out the quote and taking it to JB HiFi or Officeworks to see if they will match or beat the offer by 5%. I think it is unlikely but worth a try. Officeworks has been beating Catch of the Day's external hard drive prices by 5% (with a simple print out).
Remember if you depart the country within 30 days remember to claim back the gst through the tourist refund scheme (http://www.customs.gov.au/site/page.cfm?u=4646)
You can try using the developers store without being a member or a student but the purchase may not go through (see below).
Terms:
"Student Members may take advantage of a special, one-time hardware discount per lifetime (this benefit is non-renewable and subject to change). You must verify your student status and hold an active ADC Student Membership before ordering hardware. Orders will be cancelled if student status has not been verified"
(The biggest discount is with the MacBook Pro and the Air, and decreases for the MacBook. A discount also applies to things like the Time Capsule and other Mac products so it is best to buy all at once)
Good find. Thanks