The Seasonic SS400-HT is an 80PLUS approved PSU(very high quality it shows), and it is made for servers. That doesn't matter, unless you care about screws putting the thing tightly in place because you take it to lan parties a lot. The thing has the circuitry of an S12-500, with much higher efficiency, and is very quiet. I would say the 400 watts would be enough, and probably the best PSU you could get right now in terms of efficiency, noise, reliability, and price.($85 shipped depending on location.) can be found at casemod.com