Hi,
That's quite a decent machine. Some questions though: Will you be building it yourself? If so, you'd get all that quite a bit cheaper than £1500. Do you intend to utilise it's full potential? I've been told there's not a lot of software out there that utilises multi core processors. I've just spent a little under £500 building my own (excluding monitors and case):
ASUS P5W Deluxe Digital Home MoBo
2 x 1GB of the same RAM you've got listed*
ATI X1950 Pro 256MB Graphics card
Intel E6600 Core 2 Duo 2.40GHz - overclocked to 3.0GHz with stock Heatsink and Fan
500w power supply.
I'm more than impressed with the performance.
* I remember reading somewhere not to install any more than 3GB RAM if using Windoze XP as more than 3GB wont be recognised. Think that was specific to my MoBo though.
Might be worth checking out
www.scan.co.uk and
www.overclockers.co.uk for prices.
Hope that helps,
AV8.