I'm really not sure it's worth going i7 for gaming. i5 7xx is every bit as fast in gaming - in fact slightly faster due to the on-chip pcie controller. Check out some benches. This build is a similar price to the i7 build but trades i7 for xfired 5850s instead, keeps your bluray drive and adds a conventional HDD for storage (that little SSD could be full very quick!).
OCZ Vertex 2E 120GB 2.5" SATA-II Solid State Hard Drive (OCZSSD2-2VTXE120G) £232.64
2x XFX ATI Radeon HD 5850 1024MB GDDR5 PCI-Express Graphics Card ***Supplied with Stalker & Assasins Creed Games*** £399.48
Intel Core i5 760 2.80GHz (Lynnfield) (Socket LGA1156) - Retail £158.99
Antec 1200 Twelve Hundred Ultimate Gaming Case - Black £124.98
Asus P7P55D-E Intel P55 (Socket 1156) DDR3 Motherboard £109.99
Antec TruePower New Modular 650W Power Supply £89.99
Corsair Dominator 4GB (2x2GB) DDR3 PC3-12800C9 1600MHz Dual Channel Kit (CMD4GX3M2A1600C9) £76.36
Corsair H50-1 High-Performance CPU Watercooler (Socket LGA775/1156/1366/AM2/AM3) £62.99
Samsung SH-B083L/RSBP 8x BluRay ROM / 16x DVD±RW Drive - Black (Retail) £45.99
Samsung SpinPoint F3 500GB SATA-II 16MB Cache - OEM (HD502HJ) £32.99
Sub Total : £1,135.67
Shipping : £14.75
VAT is being charged at 17.50% VAT : £201.32
Total : £1,351.74