I need your PSU recommendation

Hello there,

I am buying a new pc consisting of an I7 2600 processor, Asus p8p67 motherboard, 6gb 2000 mhz ddr3 memory, 1280 mb gtx570 graphics card, an ordinary dwd-rw, a 24" monitor, a 1TB sata3 hdd and an external audio card.

My question is: How many watts of capacity should a PSU have for this system? Do you think buying a 600WATT PSU, or a case that includes such a PSU, would be enough?

Thanks very much.