Just to expand on Recruits suggestions, for <5m go for the molex cable, for 5m or greater it is worth looking at Markgrants own branded cables (personally I wouldn't cough up for the more expensive 'bettercables' product unless you can get what you want in Joe F's power buy). For much better value on longer leads I recommend importing from a reptable supplier such as BlueJeansCables in the US...