You actually seem to know what you're doing for the most part. The psu brand isn't that good, switched it out for a better one: http://pcpartpicker.com/part/xfx-power-supply-p1550sxxb9
It might have lower watts, but the manufacturer is more reliable and therefore it won't kill your system.
I would suggest a better 7970. If you can up the budget by $50, you could grab the best 7970: the Sapphire Vapor-X 7970 Ghz edition: http://pcpartpicker.com/part/sapphire-video-card-100351vxsr
Otherwise, here's some regular 7970 at the same price as your xfx one: