The HD4850 is priced nicely at ~$221, if you include shipping to Aus as well as the small difference in currencies (about 5c) that is not bad. But the HD4870 is $399 MINIMUM, with many places charging $440 for it. The GTX260 is about the same price as the 4870 and the GTX280 is $760-780 for the average lowest prices. I really don't understand why the 4850 is price ok but the others aren't.