If you overclock and at that price you might want to check the other Antec offerings. They have a power supply line where you can tweak the output voltages to match your particular systems demands. I think they were priced about the same as that model.
I would also check out PC power and cooling offerings near that range
anything over 500W should do fine... you are talking 57Amps... for the 12V rails... if your price is pretty much maxed then PC P&C might be out...
lee: i dont plan on overclocking far enough that i would need that. i would be too afraid of blowing my cpu plus my mobo can only do 350 htt. right now my opteron is at 305x9 @ 1.2875 volts. i think i could get 350 at stock volts. i would like to see the psu you are talking about though. is it the neo he?