How would you guys spend $4000 on a PC?

PCPartPicker part list / Price breakdown by merchant

Type Item Price
CPU Intel Core i7-6700K 4.0GHz Quad-Core Processor $444.98 @ DirectCanada
CPU Cooler Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler $36.75 @ Vuugo
Motherboard Gigabyte GA-Z170MX-Gaming 5 Micro ATX LGA1151 Motherboard $144.99 @ NCIX
Memory Corsair Vengeance LPX 16GB (4 x 4GB) DDR4-2400 Memory $84.88 @ Canada Computers
Storage Sandisk X400 512GB 2.5" Solid State Drive $163.62 @ DirectCanada
Video Card EVGA GeForce GTX 1080 8GB Founders Edition Video Card (2-Way SLI) $909.99 @ NCIX
Video Card EVGA GeForce GTX 1080 8GB Founders Edition Video Card (2-Way SLI) $909.99 @ NCIX
Case Phanteks Enthoo Pro ATX Full Tower Case $129.99 @ Amazon Canada
Power Supply EVGA 850W 80+ Gold Certified Fully-Modular ATX Power Supply $164.98 @ Newegg Canada
Monitor Acer XB270HU bprz 27.0" 144Hz Monitor $748.88 @ Canada Computers
Prices include shipping, taxes, rebates, and discounts
Total (before mail-in rebates) $3779.05
Mail-in rebates -$40.00
Total $3739.05
Generated by PCPartPicker 2016-06-02 17:58 EDT-0400

Here's an example build.

/r/buildapc Thread