That's quite a high budget

you could get a high end Sandy Bridge build for that:
Intel Core i7-2600K 3.40GHz (Sandybridge) Socket LGA1155 Processor - Retail £249.59
(£207.99) £249.59
(£207.99)
OcUK ATI Radeon 6950 2048MB GDDR5 PCI-Express Graphics Card £219.98
(£183.32) £219.98
(£183.32)
MSI P67A-GD65 Intel P67 (Socket 1155) DDR3 Motherboard - (Sandybridge) £134.99
(£112.49) £134.99
(£112.49)
Crucial RealSSD C300 64GB 2.5" SATA 6Gb/s Solid State Hard Drive (CTFDDAC064MAG-1G1) £99.98
(£83.32) £99.98
(£83.32)
G.Skill RipJawsX 8GB (2x4GB) DDR3 PC3-12800C9 1600MHz Dual Channel Kit (F3-12800CL9D-8GBXL ) £85.99
(£71.66) £85.99
(£71.66)
XFX Pro 650W Core Edition Power Supply £68.99
(£57.49) £68.99
(£57.49)
Samsung SH-S223C/BEBE 22x DVD±RW SATA ReWriter (Black) - OEM £11.99
(£9.99) £11.99
(£9.99)
Sub Total : £726.26
Shipping cost assumes delivery to UK Mainland with:
DPD Next Day Parcel
(This can be changed during checkout) Shipping : £10.00
VAT is being charged at 20.00% VAT : £147.25
Total : £883.51
Or if you really want to stick with AMD:
OcUK ATI Radeon 6950 2048MB GDDR5 PCI-Express Graphics Card £219.98
(£183.32) £219.98
(£183.32)
AMD Phenom II X6 Six Core 1090T Black Edition 3.20GHz (Socket AM3) - Retail £159.59
(£132.99) £159.59
(£132.99)
Gigabyte GA-890GPA-UD3H AMD 890GX (Socket AM3) DDR3 Motherboard £106.99
(£89.16) £106.99
(£89.16)
Crucial RealSSD C300 64GB 2.5" SATA 6Gb/s Solid State Hard Drive (CTFDDAC064MAG-1G1) £99.98
(£83.32) £99.98
(£83.32)
G.Skill RipJawsX 8GB (2x4GB) DDR3 PC3-12800C9 1600MHz Dual Channel Kit (F3-12800CL9D-8GBXL ) £85.99
(£71.66) £85.99
(£71.66)
XFX Pro 650W Core Edition Power Supply £68.99
(£57.49) £68.99
(£57.49)
Samsung SH-S223C/BEBE 22x DVD±RW SATA ReWriter (Black) - OEM £11.99
(£9.99) £11.99
(£9.99)
Sub Total : £627.93
Shipping cost assumes delivery to UK Mainland with:
DPD Next Day Parcel
(This can be changed during checkout) Shipping : £10.00
VAT is being charged at 20.00% VAT : £127.59
Total : £765.52