I already have the monitor, OS, mouse, keyboard, speakers, etc.
Yes, the estimated wattage is 366W. I'm not familiar of whether that's a good thing or bad thing, but I was told it's pretty low. Any insight as to whether I can change a part for the better is much appreciated.
I would just go for the 7870 XT (Tahiti LE) if you are going to spend that much money on a gpu. It has the same set as the next model up and was one of the best gpus for the money according to Tom's. I added a case and a better psu for the power of the build.
Basically, I got you a little more quality for the money.
-2013 version of the Corsair H60 (I have it, it works VERY well and it has a 5-year warranty)
-Changed your motherboard out for an ASUS that is cheaper, same specs, same 3-year warranty
-Swapped to less expensive Crucial memory, same speed, same amount (lifetime warranty)
-Bumped your storage to 1.5TB
-Changed your SSD to a more reliable/trustworthy Samsung 840
-Changed your PSU out for a modular, high-quality Rosewill CAPSTONE 550W PSU (5 -year warranty, manufactured by SuperFlower, who makes some of the best stuff right now)
Just a few notes : the samsung 840 isn't more reliable or better than the ssd you had or the a-data, it has tlc nand which is inferior to the two ssds with mlc nand, which are more reliable and faster.
The xfx 550w is made by seasonic and it's a lot more cheaper.
An aircooler is better than those closed loop watercoolers, i'd get the hyper 212 evo.
The 1.5 TB hdd is a good suggestion, you should get it, as for a card, either get the 7870 XT or the 7950, the 7870 XT is better than any 7870 and it's cheaper, the 7950 is better overall if you can pay it.