I have built one low end gaming pc before about two years ago. In the recent weeks I have been wanting to upgrade to a more high end pc. I want to start from scratch and pretty much use nothing from my current pc except for HDD.
Below I will list the components that I am thinking of getting, in the comments post your opinion my choices such as alternatives or your thoughts about my chosen parts.
NZXT Phantom (full tower)
Corsair HX-850 ATX Power Supply Modular Cables
AMD FX-8150 Eight-Core 3.6GHz
OCZ 120G Vertex III Series SSD
2 x Corsair Vengeance 1600mhz (1x8gb) DDR3
Samsung SH-B123A 12x Blu-ray/DVD Combo Drive
Sapphire ATI HD6970 2GB GDDR5
and in the way of cooling, ill do water cooling which my mate will help with
I don't think you ever become so experienced that can't benefit from outside input.
I would not choose an AMD for gaming purposes at the moment, an Intel i5 2500k is significantly faster for games, a little cheaper and use less power.
You write 2x (1x8gb) of ram. I would suggest getting a kit made for dual channel. either 2x8gb or (cheaper) 4x4gb.
The HX850 is probably good for delivering at least 1000w, so even with years of degrading it will be overkill. If you plan to upgrade to crossfire later it might be appropriate however.
Lastly, it will probably not be that long before Nvidia comes out with their new cards, and things might happen to GPU prices after that. So that is something to consider aswell.
I am thinking of crossfiring later but i am still not sure. so im getting the hx850 just incase. because if i get the 600-650 and then decide to crossfire i dont just have to buy a new gpu but a psu too! and the reason i said 2x (1x8gb) is because the store im buying from doesnt have 2x8gb.
That is true aswell. I think 6GB is about the point at which more becomes pointless at the moment, and even 3-4 years into the future 16gb will likely be plenty, so going with 2x4gb seems like a good option (try to go with a popular model from a big brand, so you can get 2 more that are exactly the same later)