Is this a good build?

Solution
No real need for a better motherboard. Z97 allows overclocking, but the CPU isn't overclockable anyway, and there's not a good CPU cooler in the build.

I'd change the power supply, there are better units available at lower prices. Maybe also the case, but that's also a matter of personal preference to some extent. You can also save some money by stepping down from a Core i5-4590 to a 4460 that is only marginally slower. With those changes you could end up with a system like this:

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4460 3.2GHz Quad-Core Processor (£127.14 @ Aria PC)
Motherboard: ASRock H97 PRO4 ATX LGA1150 Motherboard (£65.45 @ More Computers)...
No real need for a better motherboard. Z97 allows overclocking, but the CPU isn't overclockable anyway, and there's not a good CPU cooler in the build.

I'd change the power supply, there are better units available at lower prices. Maybe also the case, but that's also a matter of personal preference to some extent. You can also save some money by stepping down from a Core i5-4590 to a 4460 that is only marginally slower. With those changes you could end up with a system like this:

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4460 3.2GHz Quad-Core Processor (£127.14 @ Aria PC)
Motherboard: ASRock H97 PRO4 ATX LGA1150 Motherboard (£65.45 @ More Computers)
Memory: Crucial Ballistix Sport 8GB (2 x 4GB) DDR3-1600 Memory (£67.56 @ More Computers)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive (£35.94 @ Aria PC)
Video Card: Asus GeForce GTX 770 2GB DirectCU II Video Card (£229.99 @ Amazon UK)
Case: Corsair Graphite Series 230T Black ATX Mid Tower Case (£53.66 @ CCL Computers)
Power Supply: EVGA SuperNOVA NEX 650W 80+ Gold Certified Fully-Modular ATX Power Supply (£64.98 @ Ebuyer)
Optical Drive: LG GH24NSB0 DVD/CD Writer (£14.89 @ Amazon UK)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) (£69.65 @ CCL Computers)
Monitor: Asus VE247H 23.6" Monitor (£124.98 @ Ebuyer)
Total: £854.24
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-08-20 16:12 BST+0100
 
Solution
Some price skimming...

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4590 3.3GHz Quad-Core Processor (£140.07 @ Ebuyer)
Motherboard: ASRock H97 PRO4 ATX LGA1150 Motherboard (£65.45 @ More Computers)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1866 Memory (£61.64 @ Ebuyer)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive (£35.94 @ Aria PC)
Video Card: Asus GeForce GTX 770 2GB DirectCU II Video Card (£229.99 @ Amazon UK)
Case: Corsair 300R ATX Mid Tower Case (£58.19 @ Aria PC)
Power Supply: XFX 750W 80+ Bronze Certified ATX Power Supply (£58.99 @ Amazon UK)
Optical Drive: Samsung SH-224DB/BEBE DVD/CD Writer (£11.99 @ Ebuyer)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) (£69.65 @ CCL Computers)
Monitor: BenQ GL2460HM 60Hz 24.0" Monitor (£118.82 @ Amazon UK)
Total: £850.73
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-08-20 16:07 BST+0100

All suggested replacements are as good or better than the original in terms of quality
- Ram is better
- PSU is made by seasonic, same as the HCG 620. But this one is £20 cheaper and higher wattage
- Slightly cheaper dvd drive and monitor
 


Thank you, this is definitely more in my price range, any ideas on performance? FPS, settings, ultra?

 


Thank you! Do you have any estimates on performance, if it'll run games on ultra + fps?
 
I would also like to add that most games have AA settings (anti-aliasing) that can destroy your framerate on higher settings, but at 1080p in 98% of games you will see ZERO difference between 4xAA and 16xAA and very very little difference between 2x and 4x.

If you ever drop below 60fps in any game look at AA first.
 


Snap, hulk-smashing games on ultra at 60fps sounds like a blast, i'll be building this in a months or two, so prices may come down a tad, or I can do some upgrades..
 


I'll definitely be adding an SSD in my build at some point.
 
I like your avatar major trouble, it warms the cockles of my heart :)

Yes SSDs are great for making the system feel more 'snappy' (although it doesn't affect FPS). A decent 120gb here in the UK costs around £55

Reso my advice would be to make another post a day or two before you order so we can check the pricing for you and make sure you get the best bang for your buck, those prices are sure to change before then
 


It'll be around christmas time before I start ordering parts... I'll make a new build then.
 


Maxwell is just a codename for the GeForce 800 series? So I should just stay with my i5 and GTX 770?
 


You could do, let's see what the benchmarks bring when the 800 series is out :)
 


Thanks for the remark on my Avatar. I am pretty chuffed with it as well.

You can get 240gb SSD for under £100 in the last few months which is pretty incredible considering how much they used to cost. OP has a pretty high end built and I think an SSD (if his budget stretched enough) would be a bit of icing on the cake. I love Windows booting in under 10 secs and programs loading almost instantly giving that 'snappy' feel you describe. The other benefits is maps/levels load faster so you can be one of the first in on online games. Once you've had an SSD in your system you don't want to go back. It's much easier to put one in for your build than to have to add it later and re-install Windows and all your programs to get the full benefit from and added SSD. If he can stratch to it I would add one but as you say it does not increase fps so in not essential in a good gaming build.