Ok buddy, gotcha a build. It's pretty much the best you can get for the money.
-It's a nice, roomy case with sexy LED's.
-It has a very powerful ATI 6870, which will max/almost max games at your resolution.
-The core i3-2100 is a powerful CPU, competing with AMD quad's and beating them in gaming.
-The Spinpoint F3 hard drive is blazing fast. I have one.
-Mobo supports USB3 and Sata3. Even CrossfireX!
-4GB of nice ram. Nuff said.
-500w 80+ psu. Good deal.
Now, this sytem is overkill. It really is. I went a little over budget (£30) but you should be able to scrape up a little cash, right?
Intel Core i3 2100 3.10GHz Socket 1155 3MB L3 Cache Retail Boxed Processor
http://www.ebuyer.com/product/254976
Asus P8H67-M R3 H67 1155 Socket 8 Channel HD Audio mATX Motherboard
http://www.ebuyer.com/product/261837
Corsair 4GB (2x2GB) DDR3 1333MHz Memory Kit Unbuffered CL9
http://www.ebuyer.com/product/178943
Microsoft Windows 7 Home Premium w/SP1 - Licence and media - 1 PC - OEM - DVD - 64-bit - English
http://www.ebuyer.com/product/259863
Coolermaster HAF 912 Plus Case
http://www.ebuyer.com/product/239757
XFX HD 6870 1GB GDDR5 Dual DVI HDMI Dual Mini Display Port Out Graphics Card
http://www.ebuyer.com/product/244474
Corsair 500W CX Series PSU
http://www.ebuyer.com/product/240999
Samsung SpinPoint F3 500GB Hard Drive SATAII 7200rpm 16MB Cache - OEM
http://www.ebuyer.com/product/146252
Comes to £530 before shipping.
Hope that helps!