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Okay, here's the core:
The only thing to add is a SSD that you can snipe on sale, and a case. This is a top of the line, best parts out there type of build pretty much.
I included a 144Hz monitor because 144Hz > 1440P. Trust me on this. If you are iffy, you can try out a few games on some of my 120Hz monitors if you'd like, then decide later.
The 7970 comes with Crysis 3 and Bioshock Infinite for free, pretty good deal. Though, there isn't really much out there than can max out Crysis 3 right now. You'd need to look at spending $2k on videocards alone to get there. What I suggest is hanging on to this 7970 until the next generation of cards release, sell it, then buy the new GTX 780 or 8970.
For a case, I'd suggest the Fractal Define R4, Fractal Define Mini, Lian Li PC-7HX, or Arc Midi R2.
You will want to add either a CM Storm Spawn, Corsair M65, or Sensei Raw. Again, if you want to try these out, you are welcome to do so before biting the bullet on my system. I heavily suggest the Sensei Raw.
For the single best pair of gaming cans, I really suggest the Sennheiser 363Ds. They are really pricey though. For other stuff, check out the OP. The AD700s are an amazing headset at $100. The onboard sound on the Maximus V Gene is really great too.