£2000 is a lot of money to spend on a gaming build to say the least. Im assuming you already have all the peripherals (mouse, monitor etc.). The build I threw together is pretty much the best gaming performance you can get atm. Ofcourse all of this is subject to change, as pc hardware market is developing extremely quickly and new hardware might be considered outdated in a year or so. This could be a complete overkill depending on your resolution and games you play.
Good luck
PCPartPicker part list:
https://uk.pcpartpicker.com/list/nRMMV6
Price breakdown by merchant: https://uk.pcpartpicker.com/list/nRMMV6/by_merchant/
CPU: Intel - Core i7-8700K 3.7GHz 6-Core Processor (£279.01 @ Amazon UK)
CPU Cooler: Corsair - H150i PRO 47.3 CFM Liquid CPU Cooler (£143.04 @ Aria PC)
Motherboard: Asus - ROG STRIX Z370-E GAMING ATX LGA1151 Motherboard (£185.00 @ Aria PC)
Memory: G.Skill - Ripjaws V Series 16GB (2 x 8GB) DDR4-3200 Memory (£169.99 @ Amazon UK)
Storage: Samsung - 850 EVO-Series 500GB 2.5" Solid State Drive (£103.14 @ Aria PC)
Storage: Seagate - Barracuda 2TB 3.5" 7200RPM Internal Hard Drive (£46.95 @ Aria PC)
Video Card: MSI - GeForce GTX 1080 Ti 11GB GAMING X Video Card (£802.99 @ CCL Computers)
Case: Fractal Design - Define R6 Black TG ATX Mid Tower Case (£114.99 @ CCL Computers)
Power Supply: EVGA - SuperNOVA G3 750W 80+ Gold Certified Fully-Modular ATX Power Supply (£112.13 @ Ebuyer)
Operating System: Microsoft - Windows 10 Home OEM 64-bit
Total: £1957.24
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-05-25 20:38 BST+0100