get the Xclio 700w version, its only £64 and its very good.
check out scans today only offers
http://www.scan.co.uk/todayonly/
the 8800gts is £246, the e6600 is cheaper and the samsung drives are £2 cheaper, so re add them so you get the discount in your basket. as for the case, id say get a coolermaster cavalier or elite black midi one, the cavalier is more than the akasa one but the finish and quality makes up in the price, the elite black is more cheaper than the akasa and its still a good case, with a side vent for airflow direct to the cpu.