This is the cheapest I've seen a GTX 680 anywhere. Currently priced at USD $499 + delivery, which comes to about AUD $535 total. It is virtually impossible to find a GTX 680 below $600 locally, and local prices for this particular one are near $700 (excluding delivery!):
I bought one of these cards from Amazon.com when they were first released (paid a bit more than the current price, but still well below local retail) and haven't had any issues at all. The card is great, plays everything on max settings and it came with a free copy of Assassin's Creed 1, 2 and Revelations.
Experience game-changing performance with the ZOTAC GeForce GTX 680 powered by a powerful new GeForce architecture that redefines smooth, seamless and lifelife gaming. The ZOTAC GeForce GTX 680 raises the performance bar with new NVIDIA GPU Bost technology that maximizes clock speeds on the fly for maximum performance in every gaming scenario. New NVIDIA Adaptive Vertical Sync technology adapts the monitor's vertical-sync dynamically to current frame rates for maximum gaming smoothness and playability with the ZOTAC GeForce GTX 680. Take your gaming experience to the next level with NVIDIA Surround technology for an unmatched immersive gaming experience with a single ZOTAC GeForce GTX 680 graphics card and triple displays.