here are my specs:

Intel Core 2 Duo E6750 G0 SLA9V Conroe 2.66GHz LGA 775
ASUS P5K-E/WIFI-AP LGA 775 Intel P35 ATX
NViDia GeForce 7600GT 256MB 128-bit GDDR3 PCI Express x16 SLI Supported
A-DATA Vitesta Extreme Edition DDR2-800 2GB Memory Kit
SAMSUNG 941BW Black 19" 4ms (GTG) DVI Widescreen LCD Monitor
Seagate Barracuda 320GB 7200 RPM SATA 3.0Gb/s
LITE-ON 20X DVD±R DVD Burner with LightScribe Black SATA
COOLER MASTER Centurion 5 Black Aluminum Bezel , SECC Chassis ATX Mid Tower

normal and overclocked ^_^


thanks ^_^

a 500 watt quality one would do just fine, you dont have much "extreme" stuff

You could probably even get away with a 400W PSU.

20-25A on the 12V rail from a quality PSU would do. Most 350-400w Quality PSU's would do for that setup. If you upgrade the GPU you would need something with more power, so getting a 400w+ PSU would allow you to keep the PSU longer and not have to spend more $ next time you upgrade.
Summary:
350-400w Quality PSU now with current setup (20-25A on 12V rail(s))
400w+ for future upgrades (Antec 430w EW/Corsair 450w/PCP&P 470w)

A Corsair VX-450 would be a good choice, if you want a little upgrade room a Corsair VX-550 or HX-520 are good choices. You could also look at the Antec Earthwatts or NeoPower 500W versions. The Silverstone ST50-F is a good 500W choice too, or the PC Power and Cooling Silencer 470W.