Gaming PC under £1000

Heya bud!

I have a gaming PC setup for £600 which will last 4 years and play almost all games on the highest Res!

CPU: Intel Core i5-4570 3.2GHz Quad-Core Processor (£146.52 @ Amazon UK)
CPU Cooler: Xigmatek EP-CD903 61.2 CFM Sleeve Bearing CPU Cooler (£16.24 @ Amazon UK)
Motherboard: Gigabyte GA-B85-HD3 ATX LGA1150 Motherboard (£66.88 @ Amazon UK)
Memory: Corsair Vengeance LP 8GB (2 x 4GB) DDR3-2133 Memory (£53.49 @ Amazon UK)
Storage: Western Digital RE3 1TB 3.5" 7200RPM Internal Hard Drive (£37.00 @ Amazon UK)
Video Card: Asus GeForce GTX 650 2GB Video Card (£89.98 @ Amazon UK)
Wireless Network Adapter: TP-Link TL-WDN4800 802.11a/b/g/n PCI-Express x1 Wi-Fi Adapter (£25.98 @ Amazon UK)
Case: Corsair 200R ATX Mid Tower Case (£47.98 @ Amazon UK)
Case Fan: Cooler Master R4-L2R-20AC-GP 69.0 CFM 120mm Fan (£5.97 @ Amazon UK)
Case Fan: Cooler Master R4-L2R-20AC-GP 69.0 CFM 120mm Fan (£5.97 @ Amazon UK)
Power Supply: XFX 850W 80+ Bronze Certified ATX Power Supply (£79.99 @ Amazon UK)
Optical Drive: LG GH24NS95 DVD/CD Writer (£17.35 @ Amazon UK)
Total: £593.35

All parts are compatible and found on Amazon!

If you want any help on anything at all, just message me

Yeah there are always ways to improve it, for example the CPU could go from the I5 range (The middle of the range at the moment) to the I7 Range (the highest) for a lot more performance and multitasking.
The RAM can go up if you wanted it to, but it all depends on the kind of games your going to play. If you play LOL (League of legends) then 8GB is fine, but if your going to be playing an awful lot of BF4 and games like that, then maybe 12 or 16 would be good.
GPU is 2GB but can always change the Make for a slightly better model. The current one is fine, but sometimes certain models and companies are better than one another (Like intel and AMD)
HDD could definitely be improved if you wanted it too, the more the merrier! I would either think about having 1 HDD and a smaller SDD if you wanted, this will enable you to split up your drives from gaming and work and so on.
If your thinking of going pretty much bang on £1000 then you can definitely improve the build a lot more, but if your thinking an extra hundred or two, i would only say to improve the CPU.
Message me if you want me to put together a custom build for you based on this or your likings, and always here if you need any help.

I've gone away and made some improvements! Here they are:
I improved the CPU from a normal i5 to a i7 k (this just means the CPU is unlocked and you can change it, but that's nothing you'd probably do)
The RAM i doubled from 8GB to 16GB of corsair Vengeance
I added another SSD for extra storage (256GB corsair) and increased the HDD from 1TB of Western Digital to 2GB of Seagate.
These things will improve the actual hardware by quite a lot, but i also have a few things to say about the build.
Seeing how i changed the HDD from 1TB to 2TB you probably dont need the SSD, but it's helpfull to have and always handy for if you want to backup on another harddrive! If you do choose to remove the SSD you will save yourself £138, meaning you can improve the fan and the PSU meaning better cooling (personally i'd put in a water cooling)
For now i'll put the current build, if you want me to remove the SSD or anything else and put better cooling on, please feel free to say! Here is the new build and price:

CPU: Intel Core i7-4770K 3.5GHz Quad-Core Processor (£257.15 @ Amazon UK)
CPU Cooler: Xigmatek EP-CD903 61.2 CFM Sleeve Bearing CPU Cooler (£9.99 @ Amazon UK)
Motherboard: Gigabyte GA-B85-HD3 ATX LGA1150 Motherboard (£69.19 @ Amazon UK)
Memory: Corsair Vengeance 16GB (2 x 8GB) DDR3-1600 Memory (£127.58 @ Amazon UK)
Storage: Corsair Neutron Series 256GB 2.5" Solid State Disk (£158.89 @ Amazon UK)
Storage: Seagate Constellation ES.3 2TB 3.5" 7200RPM Internal Hard Drive (£138.50 @ Amazon UK)
Video Card: Asus GeForce GTX 650 2GB Video Card (£89.98 @ Amazon UK)
Wireless Network Adapter: TP-Link TL-WDN4800 802.11a/b/g/n PCI-Express x1 Wi-Fi Adapter (£25.98 @ Amazon UK)
Case: Corsair 200R ATX Mid Tower Case (£47.98 @ Amazon UK)
Case Fan: Cooler Master R4-L2R-20AC-GP 69.0 CFM 120mm Fan (£5.99 @ Amazon UK)
Case Fan: Cooler Master R4-L2R-20AC-GP 69.0 CFM 120mm Fan (£5.99 @ Amazon UK)
Power Supply: XFX 850W 80+ Bronze Certified ATX Power Supply (£79.99 @ Amazon UK)
Optical Drive: LG GH24NS95 DVD/CD Writer (£17.35 @ Amazon UK)
Total: £1034.56

You can do better than a GTX650 with that budget... And it will not "last 4 years and play almost all games on the highest Res". You need to reorganize your spending, 16GB of RAM and an 850 watt PSU are complete overkill and a waste of your budget. Not to mention an overclockable CPU and a motherboard that won't allow it.

Here is a something that better spends your money:

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: Intel Core i5-4670K 3.4GHz Quad-Core Processor (£164.99 @ Aria PC)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler (£23.98 @ Scan.co.uk)
Motherboard: Gigabyte GA-Z87X-D3H ATX LGA1150 Motherboard (£101.84 @ Scan.co.uk)
Memory: Kingston HyperX Grey 8GB (2 x 4GB) DDR3-1600 Memory (£59.95 @ Amazon UK)
Storage: Samsung 840 EVO 120GB 2.5" Solid State Disk (£69.49 @ Amazon UK)
Storage: Seagate Barracuda 2TB 3.5" 7200RPM Internal Hard Drive (£59.99 @ Novatech)
Video Card: Gigabyte GeForce GTX 770 2GB Video Card (£249.32 @ Scan.co.uk)
Case: Fractal Design Arc Midi R2 (Black) ATX Mid Tower Case (£69.65 @ Dabs)
Power Supply: XFX ProSeries 750W 80+ Gold Certified Fully-Modular ATX Power Supply (£106.50 @ Scan.co.uk)
Optical Drive: Lite-On iHAS124-04 DVD/CD Writer (£13.18 @ Scan.co.uk)
Operating System: Microsoft Windows 8.1 - OEM (64-bit) (£86.76 @ Amazon UK)
Total: £1005.65
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-12-20 17:15 GMT+0000)

The i5 and i7 offer the same performance in games, save some money and put it towards a better GPU by going with the i5.

The Hyper 212 EVO will handle a decent overclock and keep your CPU cool and quiet.

This motherboard does support overclocking, and if you want to add a second GPU down the road, you have that option.

8GB is more than enough RAM for gaming and multi-tasking.

120GB fast SSD for your OS and applications, and a 2TB storage drive for media and games.

The GTX770 is leaps and bounds better than a 650, you can max any game at 1080P and it will likely continue to do so for a couple more years at least.

Fractal Design makes great cases, this one has excellent airflow and cable management, removable drive trays, a window, and is very good quality.

XFX power supplies are made by SeaSonic, this one is fully modular and gold rated, and lets you SLI in the future. If SLI is not a consideration, drop down to the 650 watt version.

This computer will be much much faster for gaming, and is a better way to spend your money.