AMD Phenom II X4 955 Black Edition € 137,-
Scythe Mugen 2 Rev. B € 31,95
Gigabyte GA-770TA-UD3 € 77,85
Kingston ValueRAM KVR1333D3N9K2/4G € 89,20
Sapphire HD5850 1GB GDDR5 PCI-E € 232,-
Cooler Master CM 690 II Advanced Zwart € 77,94
be quiet! L7 530W € 49,99
Sony AD-7240S € 18,33
Samsung Spinpoint F3 HD103SJ, 1TB € 69,-
This is what they recommend in a dutch best buy guide, probably a bit over your budget with ~790 euro, but i guess you could shave some off with a cheaper videocard and using the stock cooler nad getting a different case that already comes with a PSU.
Allthough no clue what these parts cost in uk.