Like i said in the PM, its not general enough but still some useful information.
A good palce to build to your budget on current hardware.
LambdaTek PC Designer
Pick and match, the system shows you compatability ect just follow it through, go back and change if your not happy ect.
For non Brittish people,
XE.com - The World's Favorite Currency and Foreign Exchange Site and convert your ammount you have from Currency X to GBP then follow it though as normal.