Thoughts on budget itx build

You did a good job. Considering that the products on PCPartPickerAU are quiet expensive and you do not have plenty of options especially for ITX.

Does it have to be ITX ?

Why not microATX ? Should be easier to find parts
 
Cheers. I just changed the motherboard to a microATX model which saved around $20. Just making sure the PC will be able to run minecraft smoothly.
 
Cheers!

Here a better option for you.
It is an microATX and you have a better build IMO

PCPartPicker part list: http://au.pcpartpicker.com/p/3Bh5O
Price breakdown by merchant: http://au.pcpartpicker.com/p/3Bh5O/by_merchant/
Benchmarks: http://au.pcpartpicker.com/p/3Bh5O/benchmarks/

CPU: AMD A4-5300 3.4GHz Dual-Core Processor ($49.00 @ CPL Online)
Motherboard: ASRock FM2A55M-HD+ Micro ATX FM2+ Motherboard ($62.00 @ CPL Online)
Memory: G.Skill 4GB (2 x 2GB) DDR3-1600 Memory ($53.99 @ Mwave Australia)
Storage: Western Digital Caviar Blue 500GB 3.5" 7200RPM Internal Hard Drive ($55.00 @ PCCaseGear)
Video Card: Gigabyte GeForce GT 640 2GB Video Card ($99.00 @ PCCaseGear)
Case: Silverstone PS08B (Black) MicroATX Mid Tower Case ($45.00 @ CPL Online)
Power Supply: Silverstone Strider Essential 500W 80+ Certified ATX Power Supply ($59.00 @ PCCaseGear)
Optical Drive: LG GH24NSB0 DVD/CD Writer ($21.00 @ Mwave Australia)
Operating System: Microsoft Windows 8.1 (OEM) (64-bit) ($115.00 @ CPL Online)
Monitor: BenQ GW2255 60Hz 21.5" Monitor ($139.00 @ PCCaseGear)
Keyboard: Gigabyte GK-KM6150 Wired Standard Keyboard w/Optical Mouse ($12.00 @ CPL Online)
Total: $709.99
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-04-30 22:58 EST+1000)