SecretMaster

Several things. I'd honestly recommend just making the jump to the 9850 BE. It's clocked faster and has an unlocked multiplier so if you do want to ever get into OC, you'll get the most out of your money. AMD dropped the 9850 down to $205 recently, but if you are down in Australia I don't know if those price cuts would reach you.

Secondly, I'd say ditch the 1GB 9600GT and go for a 4850 of some kind. For the same price you can get a world's difference in graphical horsepower. Also note that 1GB of video RAM does very very little for actual in game performance. The only time where you'll need 1GB of V-RAM is if your playing a game like Oblivion with all the new and improved texture mods released. That is the only case I can think of where you need 1GB. 512 should be more than enough.

Also if you are intending to build this computer without any future upgrades on it, go for a OEM version of Vista. I'd say a OEM Vista 64 bit. OEM makes it considerably cheaper, but the caveat is you can only do a limited amount of hardware upgrades before it gets locked. Also with 64 bit, you can exceed the 4GB limitations with 32bit OS's. I'd say go for Vista 64 bit and put another 2GB of RAM. DDR2 RAM is extremely cheap nowadays.