How much watt i need

[hotboyz012345]

Please tell me how much watt i require for my pc. My system would be core i7 2600,hd6950,4gb ram,1tb hard disk, gigabyte p67ud4. I m non overclocker and don't use crossfire so please tell me

 

[cjl]

For a system like that, I'd get a good 550 watt or so.