First time building a PC

Azza871

Honorable
Apr 19, 2013
6
0
10,510
So, this is the first time I will be building a PC. I already have one built from last year but it has some problems I can't figure out and it just seems better to replace the 3 parts I've narrowed it down to than pay $100 to get it checked and then more for the parts.

These are from Australia and in AUD as I live there :D

The parts I'll be buying are
Intel i5 3570 - $210
ASRock H77M MB - $79
Antec HCG-520 520W PSU - $89
Possibly, although not needed I believe, Aerocool Strick-X case - $89. Cause i like the look and am sick of plain towers :)

What I already have
Nvidia GT640
1 4GB DDR3 Corsair RAM
500GB HDD, the oldest part in there.

My main concern as this is my first PC build is, have I missed anything? Or can money be saved somewhere? I've done some research to compile the parts list. Ideally, I don't want to spend more than $600 as it'll be for casual gaming, WoW mostly.
 

Azza871

Honorable
Apr 19, 2013
6
0
10,510


What CPU would you suggest? Lower level i5 or downgrade to i3?