Okay, so since you have a budget of $2k now, you have a couple more options. First option, get two monitors, leave out the mouse/keyboard/headset for now, and with a better all-in-one water cooling kit, and arguably the best gaming GPU available right now, you can get to $2,037. Again, that's with 2 monitors, a better water cooling kit, a much better GPU, but no peripherals. That build is here
http://pcpartpicker.com/p/3rrU2 - $2,037 This is with a GTX 780 Ti, which will absolutely demolish any game you throw at it.
However, if you must have the peripherals, to stay at $2k you have to sacrifice the GPU again, and stick with the regular 780, which is still no slouch by any means.
http://pcpartpicker.com/p/3rrVK - $2,011
The third option is to go all out, get both monitors, better water cooling kit, better GPU, all peripherals, etc.
http://pcpartpicker.com/p/3rrTl - $2,221
Sorry for late response, took a few minutes to get through those builds.