http://3dmark.com/3dm11/447930
P3366 for those who can't be bothered clicking - everything at 'stock'.
CPU: £200
RAM: £67
Mobo: £67
GPU: £160-ish IIRC.
Edit: RAM is 1x4GB - not 8GB as per specs on left.
Edit 2: 4GHz CPU and 900MHz on GPU: http://3dmark.com/3dm11/448029 P3991.
Edit 3: As above with minor tweaks http://3dmark.com/3dm11/448055 P4034.