Just another addition to the thread.
Why Watts Don't Mean Jack.
The wattage of a PSU is a lame way to measure the actual output of a PSU. The total wattage given is the sum of all of the rails on a PSU added up (+3.3V, +5V, +12V1, +12V2, -12V, +5VSB). The way PSU companies will trick you, is by bumping up the Amps on the red rails. These rails are relatively minor, and don't really provide power to any of the major components of your system. However, they still count towards the total power output of the PSU, and this can skewer the numbers. The blue rails, are the important ones. The +12v rails are the ones that provide most of the power to the major parts in your system. The more Amps on this rail, the more power will be supplied to your system.
Example; 400W Forton PSU and 580W Hiper. Both are excellent PSU makers. Look at this;
Forton - +3.3V@22A, +5V@21A, +12V1@18A, +12V2@16A, -12V@0.3A, +5VSB@2A.
Hiper - +3.3V@30A, +5V@36A,+12V1@20A, +12V2@18A,-12V@0.8A, +5VSB@2.5A.
The 580W Hiper PSU has 4Amps more on it's +12v rails than the Forton does. Is 4Amps worth the difference of 180W? Don't make me laugh. So that would mean that this Forton that has been "labeled" 400W is near equal in power to a 580W PSU. Wattage doesn't mean jack.