Intel Core i5-6600K Processor 3.5GHz (Overclocked to 4.1)
16GB DDR4-3000 RAM
480GB Solid State Drive
1TB Hard Disk Drive
NVIDIA GeForce GTX 1070 8GB GDDR5
MSI Z170A M5 ( I know its not the best, but really dont want to replace the motherboard)
Wrong motherboard i listed, its really the MSI Z170A M5 Pc SystemMate
chris: It's already a great system. $200 won't provide any appreciable gains. Just blowing $200 for the sake of a meaningless upgrade is wasteful.
As the hardware is already very fast. I'd look at improving the peripherals. To improve your experience. Some things to consider.
– high quality gaming keyboard and mouse.
– game controllers like Xbox 360/One controller, steering wheel or joystick.
– save up for a 144hz, 2560×1440, GSync monitor.
– better speakers or save for very good ones.
Is there anything you are neglecting?
– More storage
– backup hard drive
– improved cooling
That's already really good. Either get games, peripherals, or save it. If you can find a 1080p 144hz monitor or 1440p 60hz monitor for $200 (right now the only one that cheap is the 1080p 144hz Acer GN246HL) that would be a great monitor to take full advantage of the 1070's power. You could get a really good mechanical keyboard like a Corsair K70 RGB (Cherry MX reds are generally the best for gaming).
Samsung 960 Pro M.2 SSD? Either that or a 6700K I guess, or a nicer case (though not sure what you have now) are the only things that would really be useful.
only thing i can think of is an i7-6700k instead, then just monitor, keyboard, mouse, like what the other are saying
A nice pretty coloured monitor.