In that price range with a 7970 i would go for one of these over the 520w Antec(Antec is Ok but there a better in that price range). http://pcpartpicker.com/part/xfx-power-supply-p1750snlb9
http://pcpartpicker.com/part/seasonic-power-supply-ss650am http://pcpartpicker.com/part/corsair-power-supply-tx750m
Also unless you plan on doing a virtualization and or heavy video work 16gb is overkill. I would get 8Gb and use that extra cash on a SSD boot drive.