Looks rather sound to me. The only thing I can't comment on is the PSU since you didn't have the model number and the links are not working. I did a check on newegg and they do have a deal on the 500R case and a AX650 650w power supply which is a high quality power supply.
One more note, if you are going to overclock may I suggest an after market CPU cooler as the stock one just plain sucks for overclocking. Something like the COOLER MASTER Hyper 212 EVO should fit your budget.
the PSU is a coolermaster gx 750w
Im also from australia, i don't know if newegg ships products to australia.
Also, if i were to choose a Z77 motherboard, which should i choose that's as good as the motherboard my friend chose for me?