How do I know what kind of power supply for my P.C. I would need?

I'm building a new custom gaming P.C. and I was wondering how many watts the power supply should be.





Btw, I would gladly accept any suggestions to modifying the parts.





The stats for the PC are as follows:





HD:


Seagate Barracuda 7200.10 500GB 3.5" SATA 3.0Gb/s





RAM:


Crucial 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2





MOTHERBOARD:


GIGABYTE GA-965P-DS3 LGA 775 Intel P965 Express ATX





PROCESSOR:


Intel Core 2 Duo E6400 Conroe





MONITOR:


SAMSUNG 226BW





SPEAKERS:


Logitech THX Z-5300e 280 Watts RMS 5.1





SOUND CARD:


Bluegears b-Enspirer 7.1 Channels 24-bit 192KHz PCI Interface





VIDEO CARD:


EVGA 640-P2-N821-AR GeForce 8800GTS 640MB 320-bit GDDR3 PCI Express





CPU COOLER:


ARCTIC COOLING Freezer 7 Pro 92mm





OPTICAL:


LITE-ON Black 20X DVD±R DVD Burner W/ 12X DVD-RAM write and LightScribe

How do I know what kind of power supply for my P.C. I would need?
Get at least a 550 watt power supply the larger the better. That way if you add more peripherial devices you will have enough power to handle the load.
Reply:man 400W-500W will work
Reply:I got alot of my computer too I am using an 550 watts and it working fine.
Reply:I have a simple answer for you.If youre useing it for gameing go with the highest wattage and highest quality you can find.Check out pcworld.com.They can tell you which ones are the best.You may pay a little more for top quality,but its worth it in the long run.ATX power suppliers cost from $15.00 up to more than$200.00.PCworld.com can tell you what is best for what you want to do with yours.Hope this helps
Reply:i think no matter what accessories you add.the powersupply for all pcs are same.so y dont you ask your frnd or something
Reply:Since you are building a gaming PC, you are likely to upgrade components as better stuff becomes available. In general, more powerful components, especially video cards, require more power. Since you have an ATX mobo, you need an ATX power supply. Go with the biggest ATX power supply you can afford now, and you won't have to replace it as you upgrade your machine in the future. I would use a 700 watt power supply as a minimum.
Reply:At least 500 watts. When it comes to power supplies to much is always good.