A good 500W should be plenty, but I'd still go with a 600W or 650W.
http://www.newegg.com/Product/Produc...82E16817139028
This one is $70, with free shipping, a $12 discount coupon code, and a $20 mail-in rebate. That's pretty awesome, and it's a decent-to-good PSU.
XI Wiki



