My first ever gaming PC?

[rhiannonE]

May I suggest going with an AMD solution. It is significantly cheaper and almost as powerful as using Intel, unless you are looking into a multiple graphics solution. Something like this as a CPU and this for a MoBo.
Also 16 GB of RAM is somewhat wasteful 8GB (2x4GB) should do fine.
Finally go with a Full ATX case, you'll have space, all of it.

[Master Gunner]

My personal preference is with Intel, but I've had some bad experiences with AMD in the past.

[Darkobra]

I'm an Intel man myself. Started off with it, never had a problem with it, stuck with it. Actually actively sought it out when I built my Goliath.

[korvys]

Oh right, Australia. Well then, I recommend http://www.umart.com.au

They sell all the parts if you want to do it yourself, they sell pre-built systems (and as they are a hobbyist type place, without a huge mark up and bloatware you'd get from somewhere like JB Hi-Fi), or you can customise your own, and they'll assemble it for you.

Obviously you'll still need to do some research on what you want, but that's where I buy my hardware from.