That Corsair 520HX is more than enough for that budget system. Even under heavy overclock. I would probably get the SeaSonic 550w though, over the 520HX, because it's the same price, not considering the rebate.
Why is it I see alot of folks recommending 600+ Watt PSUs than for system builds that do not look much more power intensive than this budget build? Still learning this PSU stuff which is why I am asking.