Sorry for the slow reply. But thank you for the responses. Today i tested my power supply and it is still working fine after the pc failure, so i will be reusing it as well as the hard drive for the short term. So the suggestion by LukieBoy looks extremely delicious for a new build. The only question i have is is it worth getting a new DVD ReWriter, as mine might be about 5 years old now from, but it's been rarely used. Is there any difference between ones sold now and those sold 5 years ago? As I could drop it off the list to save me some cash.
I have also been thinking about my current case, the Antec SLK3000, replaced by the Sonata IV. Would that case provide sufficient cooling for the more powerful build as it has less positions for fans? It's served me well and only has scuff marks on it. I don't know if it would fit the above cards either. It 'just' fits my GTX 275 with about 5mm to spare. How much bigger are the newer ATi cards?
I'm thinking if i can get everything on LukieBoy's list except the case and writer and save 100 pounds in the process that'd be great. Unless people feel the upgrade is necessary.