You could upgrade to the AMD Phenom II X4 955 if you're comfortable paying closer to £700. The motherboard allows for crossfiring, there are other motherboards that have SATA 6GB/s ports, so if you think you would interested in adding a fast SSD at any point then it would be a good idea to get one of those. If you want a larger harddrive: Samsung Spinpoint F3 1TB £62.
The price only comes to roughly £40 more than the components you outlined earlier, which seems like pretty decent value considering the upgrade of the processor. I was just wondering if you knew how the Geil memory compares to the Ripjaw, because I've not seen it before?