Cooling system

What kind of cooling would I need for a rig like this:

Q6600 (G0) over clocked to about 3.0Ghz - 3.2Ghz

2 8800gts 512mb in SLI (probably overclocked)

750i FTW

4gb DDR2 800mhz (probably overclocked)

2x 500gb HDD

850w

NZXT zero case

Also I live in Australia so it can get pretty hot during the summer, especially when the air con carks it.