cheap way would be build by you self (even if you dont know how local shop can do it for you for about 40 pounds -just avoid Pc world they overpriced! ) and there is few options :
AMD Phenom II X2 555 Black Edition: £85,25
4GB (2x2GB) Corsair DDR3 PC3-10666: £94,99
Asus M4A87TD EVO, AMD 870, S AM3: £91,50
1TB Samsung HD103SJ Spinpoint F3: £54,84
1GB Asus HD 5850 , PCI-E 2.0 (x16): £223,23
Windows 7 Home Premium 64bit OEM: £82.33
Total: £605,14 inc. VAT
I'd recommend for you:
Case: Antec 300
You're not looking for something insane at your price, and you'd have to compromise on other stuff if you were going to go for something more expensive.
CPU: i5 750.
Personally, I try to go by my own experiences, and so I picked you the 750. Further more, for AMD chips you really want as tight latencies as possible with the ram, whilst Intel chips don't really care how loose your memory is. But AMD are not bad ass well and cheaper
Memory: Corsair XMS3 1600MHz, 9-9-9-24
It's the cheapest 1600MHz kit on Scan. That's all there is to it.
Motherboard: Gigabyte GA-P55-US3L
It's the cheapest P55 motherboard on Scan from a supplier I trust. Gigabyte tend to make quality products, if anyone can find something else that would be better, great, but here's a nice cheap one.
Graphics card: 5850!
You can see why I've skimped so much on everything else! A 5850 will be all but essential for gaming at 1920x1200, personally I'd be wanting a 5870 for that (which clearly isn't in your budget).
Hard drive: 500GB Seagate
PSU: Corsair VX550w. It isn't much, and if you can stump up the extra £10 for the 650w that would be great. Both will work, but the 650 will give you more room for upgrades later on and will probably be quieter.
DVD drive: Anything will do.
Total price: £722.
I think that would give you some great speed, and since a significant minority of 750s nowadays can overclock to about 4GHz on the stock cooler, you should be set for some reasonable overclocking even without an aftermarket cooler.
Kingston 4GB (2x2GB) DDR3 1600MHz/PC3-12800 HyperX Memory Kit CL9(9-9-9-27 £94.20
Intel Core i5 750 2.66GHz Socket LGA1156 8MB L3 Cache Retail Boxed Processor £165.86
ASUS P7H55-M H55 Socket 1156 VGA HDMI Out 8 Channel Audio MATX Motherboard £64.99
XFX HD 5770 850MHz 1GB DDR5 HDMI Dual DVI Display Port PCI-E Graphics Card £144.52
Coolermaster Elite 330 Case with 620W PSU - 2x SATA 12cm Fan £49.99
Samsung HD103SJ Spinpoint F3 1TB Hard Drive SATAII 7200rpm 32MB Cache - OEM £55.03
Just to let ya know. I know the 5850 gfx card is better, but the XFX HD 5770 gfx card is plenty good enough.
AMD Phenom II X4 945 - 119,78
4GB (2x2GB) Corsair DDR3 PC3-10666 - 94,99
1GB XFX HD5850 - 248,37
Asus M4A88TD-V EVO, AMD 880G - 87,41
550W Corsair CMPSU-550VXUK - 69,96
1TB Samsung HD103SJ F3 - 54,84
ALL OF those configurations give You plenty power and plesure for GAMING PC
Some of great shops :http://www.overclockers.co.ukhttp://www.scan.co.uk/http://www.novatech.co.uk/novatechhttp://www.aria.co.uk
Hope thats gona help someone