Not quite. I've read tons of times that you need a uber super duper psu to juice your machine. What you need is a psu that's from a reputable company. Don't bother with the wattage what matters is the ampage.
I have a 375w dual amps (18 each) psu that powers:
1 gig mem
The pc runs for days before I give it a rest. Plenty of gaming, burning and not a single problem (knock on wood). I remember Corsair created a high end htpc with sli running on a 375w psu as well. No problems there either.