System Recomendations i5 3570k EVGA GTX 670

Well

i5 3570k
Fractal R4
GTX 670
1600 G.Skill 8GB
Asrock Extreme 4
Corsair 650TX
Samsung Pro 128SSD
1 TB WD Black

For your budget range that is a very solid CPU/GPU combo that I vouch for. The 3570k overclocks like a bat out of hell so your in luck there, that said they do run hot so you will definitely need some aftermarket cooling.
I use a Corsair Hydro Series H80 closed loop liquid cooler for my cpu and it works a treat with temps kept low and the noise much the same. However a lot of people say the closed loops are overrated so you might prefer to go with one of the Noctua air coolers which get terrific results too!
As far as your GPU goes the 670s do a fair effort of keeping themselves in good temperature ranges so a mild overclock should be fine on your stock cooling.
Best of luck with the build buddy!

Is the corsair 650TX capable of powering everything + the overclocks?

650 would be enough to power that, but you dont leave yourself room to expand to sli in the future. Get yourself a 750 or 850 if you feel you need the headroom.

Thanks, any recommendations on the motherboard?

I agree with with the Asrock Extreme 4, I use one and it's been faultless. Comes with some pretty decent software and leaves you with the option to upgrade to dual sli in the future.
If you have any other questions feel free to ask.

So since this is my first build I was wondering, is building the actual machine a complex process or is it more or less like anything else that comes in a box.

These days building a computer has become a fairly simple D.I.Y project. Your case should come with an instruction manual that will detail the installation procedure for at the very least the motherboard, and more than likely a fair chunk of the rest of the system.
It doesn't really get more complicated than screwing in screws and plugging in cables, unless you are doing a custom watercooling setup or modding your hardware.
The one thing you want to be paticularly careful of (as it will kill your hardware if you are very careless) is static electricity.
Read this article http://www.pcworld.com/article/82184/article.html and you should be fine in regards to static.
As far as actually building goes if you get stumped just go on youtube, there are a myriad of videos on there that can show you step by step how to build a pc.
Once again, feel free to ask a question if you need to.