Power consumption of core 2 quad system - power supply needed

Have a look here. Some of your components are old and may not be listed.

PSUs are one of my things, and at a punt, I'd guess around 350-400W would cover it, probably less, but better more than less. The PSU is the heart of the machine so don't scrimp by getting a generic silver box. They are very inefficient (less than 70% generally) and a safety hazard as far as I'm conceed.

Go for something that is 85+ efficiency rated by a reputable manufacturer. The extra thirty or forty bucks will be worth every cent. They have a heap of safety switches and features, will last longer than the rest of the components (probably) so you'll be able to use it for the next build. A generic silver box could disintegrate at any time taking one, some or all of the other components in your box with it, or worse, causing a fire (I have witnessed this happen).

Good luck and hope that helps.