The Seasonic S-12's are highly recommended. The only thing I dislike about them is the high cost (the Sparkle FSP550-60PLG is cheaper and better, but loud.). Also with highly overclocked CPU's the 18A may not be enough. This would only mainly be a problem with Prescotts reaching 5GHz or systems with dual CPU's though. Probably not a problem with your A64. A PSU with a single beefier +12v rail may be better though such as the Sparkle mentioned above, the OCZ Powerstream 520w or even the really expensive PC P&C 510. All of them would drive a heavier load then th4e Seasnic, but with a heavy load that requires more then the Seasnic those PSU's could get a little loud