The discussions for this question appear all over the place. For single rail PSU's, I'd like to point out that PC P&C and Corsair have been building single rail PSU's for years with none of the problems that Antec talked about in their "myths".
I would also like to point out that, in addition to 3 single rail Corsairs (two more 400CX's on order before they disappear), I own two of Antec's older "multi-rail" PSU's. They are both good, solid units (550 watt and 650 watt TP3's), but a few minutes with a DMM show that both are single rail PSU's with no isolation between the rails.
A good single rail PSU is better than a mediocre multi-rail PSU. The converse is also true.
My PSU has a switch on the back that allows me to choose single or multiple. So for the purposes of my PSU a 1000w Mushkin, I want to know if there is a preference with SLI gtx 480s and an overclocked i7 930. The gtx 480s are not overclocked.
Here are the technical specs..http://www.overclockersclub.com/reviews/mush1000w/3.htm