Firstly, I want to apologize if this is an annoying, frequently asked question. This is my first ever build and this is the only part I'm unsure of (although I'm sure building it will raise a lot more obstacles).
Here's what I have:
CPU: Intel i5 - 4570 3.2GHz
CPU Cooler: Stock Intel CPU Cooler
Video: Sapphire Radeon R9 270X 4GB
Motherboard: Gigabyte Z87MX-D3H
RAM: *(2) 4GB DDR3 1600MHz
Storage: WD Green 1TB SATA (may also buy a SSD to install the OS on: opinions?)
Fans: 1 regular 80mm
* - I haven't bought this yet! Any suggestions?
Now after doing about 5 different calculators I have results ranging from 350W to 700W. Looking around it seems 500w would be ideal maybe?
A 500W PSU would be a comfortable size. Any more than 550W will likely be a waste of money, as you'll be operating outside of the most efficient part of its range. You want a GOOD 500W PSU, such as anything built by Seasonic (their own, XFX, some Antec, some PC Power & Cooling), Superflower (Rosewill Capstone), or Delta (some Antec).
That Rosewill PSU is an obsolete, inefficient design.
The PSU calculator at http://www.extreme.outervision.com/psucalculatorlite.js... is reasonably accurate. Remember, regardless of the number of cores, you'll have ONE CPU.
SSDs use an insignificant amount of power. You'll only need 650W (or more) if you intend to run two graphics cards.
I just bought this one and it has a five year warranty and a lot of people recommend it. It has 1 6+2 pin connector and 1 6 pin connector so the connections are sufficient for R9 270x however you can go higher on the wattage if you want.