95thrifles suggestion is best if you can't/don't want to overclock yourself.
Otherwise, a 950 i7, a PX658D-E and RAM that isn't OCZ and you can't go wrong
eg.
Intel Core i7 950 3.06GHz (Bloomfield) (Socket LGA1366) - Retail £229.11
(£194.99)
Asus P6X58D-E Intel X58 (Socket 1366) DDR3 Motherboard £143.98
(£122.54)
Patriot Viper 6GB (3x2GB) DDR3 12800C8 1600MHz Low Latency Triple Channel (PVT36G1600LLK) £124.98
(£106.37)
Noctua NH-D14 Dual Radiator CPU Cooler (Socket LGA1366/LGA1156/LGA775/AM2/AM2) £66.99
(£57.01)
Sub Total : £480.91
Shipping : £9.50
VAT : £85.82
Total : £576.23
The cooler won't be in stock for another 5 days though.