I know this is an old thread, but I gotta jump in here. What's with all the discussion on watts lately? The way I look at is simply amps on the 12v rail. This is what's important. And as far as namebrand goes, well, I think we're all agreed: antec, enermax, fortron/sparkle, ocz, blah, blah, blah. They're all good and they're all playing the numbers game, with the exception, maybe, of fortron/sparkle.
Take for instance the enermax 420 that was mentioned above with "high 12v rails". That thing's putting out 15 amps on the 12v rails. Crap, my 270w fortron is putting out 16, for a lot less money. Same with the 480 this and 550 that. Regardless of namebrand, check the 12v rails. Jeez.
My recommendation for a power supply? Enermax 350. 26amps on the 12v rails. $59 from NE. Even that is a bit pricy imho. Got some kind of super system? Grab a namebrand 400+ psu with 33 -36 amps. Basic system? A 250 - 300 watt Fortron with 16 amps.
What's the big mystery? Quit playing the numbers game, and throwing your money away. 16, 26, 33, or 36 amps on the 12v rails. Those are the real choices you have to make.
Anything more than $2.25/amp is just throwing your money away. $3/amp and that sucker better be gold plated and make my coffee for me in the morning.
Am I wrong here?