2 gtx460's on the athlon II is a waste, you wont see much diff in performance with 1 gtx460. you would be better off with a faster phenom II x4 cpu and get just a single graphics card, maye gtx460 or 470. a 650w PSU from antec, seasonic, corsair is what you want. Seriously, you dont want a cheap PSU running 2 gtx460's in SLI...unless your a moron. this http://www.newegg.com/Product/Product.aspx?Item=N82E168... is the cheapest psu you could get that is also good quality. if you get something cheap like this http://www.newegg.com/Product/Product.aspx?Item=N82E168... your computer will blow up.
Just get a 470. Two gtx 460 on a Athlon ii? No. Buy one gtx 470 and then get a better PSU. If you have the money, maybe a better CPU and then two GTX 460s. But do you really need that much power? The PSU is the most important thing on a machine. If you cheap out on a PSU your whole computer might break. GTX 470s are strong. Get a good PSU to top that all off and your set. Hope I helped.
My Antec EA650 was/is great.
I recently moved to a corsair hx580 because I am planning to run a sli setup and because my wife makes more $$ than I do
I highly recommend the Antec Earthwatts, it will serve you well.