any regular atx power supply will do. The only issue you would want to be aware of is the reliability of your future power suppply. If you are money concious, i'd recommend the cooler master 500 power supply. great wattage for the money.
Funny... most coolermaster PSUs are no good (There's only one coolermaster line that has some decent quality), if you want a PSU, make sure it's something stable and powerful like Antec NeoHE, Seasonic S12/M12 series, Corsair HX/VX series are all great supporting any gaming computers, however if you are not powering a gaming pc, then I suggest getting something slightly cheaper from FSP Group, one of their 450W-500W units for around $50-60 only.