Electro, try not to be so sensitive. RC wasn't trying to be a smartass. He's trying to teach you about the question you should have asked.
And you
still have things sort of backwards.
Electro 121 :
i can talor the rest of the parts to fit the motherboard and which ever type of power supply i buy.
You gather your parts, then you select the size of the power supply that you need to power those parts.
And even that's fairly simple:
Basic computer with built in graphics - good 400 watt PSU.
Basic computer with one graphics card - good 500 - 550 watt PSU.
Basic computer with two graphics cards - good 700 -750 watt PSU.
Those recommendations will cover probably 80 - 90% of all new builds, upgrades, and replacements.
My personal choices are Corsair and Antec.