First time pc builder

PuperHacker

Honorable
This is my suggestion:
PCPartPicker part list: https://uk.pcpartpicker.com/list/XzwfdX
Price breakdown by merchant: https://uk.pcpartpicker.com/list/XzwfdX/by_merchant/

CPU: Intel - Core i5-8400 2.8GHz 6-Core Processor (£147.97 @ Aria PC)
CPU Cooler: Noctua - NH-U9S 46.4 CFM CPU Cooler (£52.99 @ Overclockers.co.uk)
Motherboard: MSI - Z370 GAMING PLUS ATX LGA1151 Motherboard (£99.96 @ CCL Computers)
Memory: Corsair - Vengeance LPX 8GB (2 x 4GB) DDR4-3000 Memory (£93.59 @ Aria PC)
Storage: Seagate - Barracuda 2TB 3.5" 7200RPM Internal Hard Drive (£50.39 @ Aria PC)
Video Card: EVGA - GeForce GTX 1070 Ti 8GB SC GAMING ACX 3.0 Black Edition Video Card (£369.86 @ Amazon UK)
Case: Phanteks - Eclipse P300 Tempered Glass ATX Mid Tower Case (£47.94 @ Aria PC)
Power Supply: Corsair - TXM Gold 650W 80+ Gold Certified Semi-Modular ATX Power Supply (£67.98 @ Aria PC)
Operating System: Microsoft - Windows 10 Home OEM 64-bit (£83.50 @ More Computers)
Monitor: Asus - VX24AH 24.0" 2560x1440 60Hz Monitor (£189.98 @ Amazon UK)
Keyboard: Corsair - K55 + HARPOON RGB Wired Gaming Keyboard w/Optical Mouse (£64.99 @ Box Limited)

Total: £1269.15
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-06-12 13:54 BST+0100
NOTES: -Why get a gtx1070 and run it at 1080p? I chose a gtx1070Ti in conjunction with a 1440p screen.
-An i5 8400 will be just fine for 1440p
-Get higher frequency RAM, a 2X4GB kit.
- I chose higher quality motherboard.
- I chose the TX650M over the TX550M, as it was actually cheaper!
Hope I helped.
 

Cioby

Distinguished
https://uk.pcpartpicker.com/list/Vx3GJ8

This is how I edited as best I could. Get some cheap keyboard + mouse, doesn't really impact as much to start with and you can always find them on sale and just pick them up later. Maybe just a mouse with at least 2000 dpi, but that's it.

You need a overclockable CPU with that cooler and config, or you'll remain behind and not juice it as much as you could've. The PSU is way too weak and bronze, protect your expensive CPU/GPU! And it might not even run at all. The storage has been known to fail, WD is better, Black is really good plus you can add later on with an SSD from Samsung for more storage. Ram, dual channel is much better and you will need the 16 nowadays. Upgrading later from a single channel to a dual channel will be more costly.

With these suggestions you can edit my build and get better stuff, those are just quick suggestions. Also you may wait for the new Nvidia generation and get cheaper stuff. Or even used 1070ti.

If you ask why not the 8700k I heard it's hot and generation gaps don't really exist for gamers at least. I still run a 4770k overclocked with a 1080ti Aorus. My benches compete with any other CPU + 1080ti. That's why overclock is very important and no it doesn't kill the CPU, mine is 6+ years old, as long as you keep it cool and below 85. (Intel runs at up to 105 but it gets a little damaged, with your water cooling, you will never get that)
 
PCPartPicker part list / Price breakdown by merchant

CPU: Intel - Core i5-8500 3GHz 6-Core Processor (£165.59 @ Aria PC)
Motherboard: Gigabyte - Z370P D3 ATX LGA1151 Motherboard (£81.59 @ Aria PC)
Memory: Team - Dark 16GB (2 x 8GB) DDR4-3000 Memory (£149.99 @ Overclockers.co.uk)
Storage: Crucial - MX500 250GB 2.5" Solid State Drive (£59.99 @ Aria PC)
Storage: Western Digital - Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive (£35.80 @ Amazon UK)
Video Card: Palit - GeForce GTX 1070 8GB Dual Video Card (£365.99 @ Aria PC)
Case: Phanteks - Eclipse P300 Tempered Glass ATX Mid Tower Case (£47.94 @ Aria PC)
Power Supply: Corsair - TXM Gold 550W 80+ Gold Certified Semi-Modular ATX Power Supply (£69.06 @ Ebuyer)
Operating System: Microsoft - Windows 10 Home OEM 64-bit (£82.99 @ AWD-IT)
Monitor: AOC - Q3279VWF 31.5" 2560x1440 75Hz Monitor (£194.98 @ Ebuyer)
Keyboard: Thermaltake - Commander Bundle Wired Gaming Keyboard w/Optical Mouse (£35.81 @ Amazon UK)
Total: £1289.73
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-06-13 16:56 BST+0100

The 1070ti prices are wrong , they're all £100 or so more than listed.