Probably the single most important thing to keep in mind about the PSU, besides reliabilty of the manufacturer, is what does it supply on it's 12v rails. I first learned about this all important aspect over at computerforums.com, specifically thier writing entitled, "PSU 101." I strongly suggest you read it. You see, you can have a power supply claiming it gives out 500 watts but if its rails fail to give the proper power where needed, so what. You'll be unpowered. And with today's hardware, especially for gaming, the PSU is crucial. Too many people cut corners here and as many people have told me the PSU is the backbone to all the rest.
Enermax, Fortran, Antec are to name a few. You can spend more if you'd like. They're out there.