What PSU wattage do I need?

Hey everyone on TekSyndicate 

I am wondering what PSU wattage I need to get. Many PSU calculators tell me 412W maximum but I am a bit skeptical about it. What would you guys say?

Specs:

1x 120MM LED FAN

FX 6100/6300 NON OVERCLOCKED STOCK HEATSINK

MSI HD 7850 OC 1GB

8GB DDR3 (2x4GB) LP Corsair

1x 500GB Barracuda, Seagate

(maybe an SSD depending on my money)

Mid end motherboard 

3x USB Device

 

 

That's all I have connected. What PSU wattage would you recommend? 450W? 500W? 600W? If I plan to upgrade, I won't be going over the top. I will only get 95W CPU's with AM3+. I will also not get any other the top GPU's if I upgrade. So, what is a good PSU for the time being out of these?

http://www.scan.co.uk/products/450w-powercool-pcpc450auba-80-plus-sli-crossfire-quiet-fan-atx-v22-psu

http://www.scan.co.uk/products/450w-xfx-pro-core-edition-p1-450s-x2b9-85-eff-80-plus-bronze-sli-crossfire-eps-12v-fan-atx-v231-psu

http://www.scan.co.uk/products/500w-silverstone-sst-st50f-es-strider-psu-silent-80-plus-atx-12v-23-24x7-use-ready!

I would like to know what I need because I am on a semi tight budget (Need to afford a monitor, a mouse and a gaming PC under £560)

Just get 500w so you have room to add harddrives or overclock a bit if you want, 450w minimum if you wanna be cheap.

What pip said. If you plan on CF'ing in the future, get a 750w.