I'm surprised no-one addressed this sooner, but WHAT kinda power supply are you getting from your cousin, Notodd?It makes no sense you spend all this money one these parts and then your power supply is some el cheapo $200 hand-me-down from your cousin. I thinks you need to tell us that exactly your cousin is giving you.
do you at all plan on xrsossfire or sli?
if yu not gonna be sli or xfire, then get a non sli board save a lil money and yeah 600 watts should suffice safely.