timmythebean,
I followed your link and read the thread. Twice you posted about people recommending power supplies that are not on a list. You specifically mentioned the Corsair 750 not being on a list and questioned why people think it can handle two 260 video cards in SLI mode. The answers are simple.
Lists are rarely all inclusive and may not be accurate.
Two GTX 260 SLI video cards operating in dual SLI mode use a combined total of 380 watts and 32 amps at full load. The source of the information is a recent article at Tom's Hardware about actual power requirements for a variety of video cards that were actually tested. The link to the article is on the home page. The charts are on page 6 of the article.
The Corsair 750TX has a large 12 volt rail rated at a whopping 60 amps! More than enough power to handle two of those 260's and the rest of the system. In fact, the rest of the system requirements are small when compared to a couple of 260's.
Corsair, PC Power & Cooling, and Seasonic are all high quality brands with an excellent reputation for stability and reliability. They consistently earn high marks in technical reviews and comparisons. Those are the three brands most often recommended by the veteran posters at this forum.
We usually see a lot of posts where individuals seriously overestimate power supply requirements. It happens all the time at this forum. Part of the problem are the psu power calculators. First, people forget it is a rough estimate for the entire system. Second, the calculators overestimate total power supply requirements because there are an awful lot cheap low quality psu's of questionable performance. For some reason people insist on buying cheap low quality psu's that can ruin other components.