Here is the build.
Please suggest appropriate power supply. Ill be gaming, hence the nice video card.
Also, a sanity check on my choice of memory please, I guessed.
There will be hard drives in the system. They are not on the system build because I am supplying them. Best guess Id say four hard drives.
Hard drives use very little power.
eXtreme Power Supply Calculator Lite
Your memory is fine.
The important measures in a power supply are efficiency (more efficient = costs less money) and 12V amperage. Almost all components run at 12V, so the 12V amperage tells you how many of its advertised Watts it can use. 12V * amperage-at-12V = actual Wattage.
Power supply output degrades with time so you want one with much higher 12V Wattage than you actually need. Also, go for ones that are bronze or better and brandwise, Seasonic is solid.
My next build will have a modular power supply, since you can unplug the cords you're not using. But if your case lets you stow away unneeded cords then you can get a non-modular one and save a few bucks.
That said, this power supply should work well, though a bronze or a silver with similar output by a reputable company would be fine too:
This one is $10 cheaper and will work fine on your build, but it's not modular: