I hate it when people measure "safe" in terms of watts. A 600W no-name PSU is far more likely to fry your system than a 400W Antec, Forton or a 430W Seasonic.
Here are some other recommendations, the 580W Hiper is good, but not necessary;
http://www.scan.co.uk/Products/Produ...oductID=442822 http://www.scan.co.uk/Products/Produ...oductID=271184 http://www.scan.co.uk/Products/Produ...oductID=256335