With the notable exception of Enermax, if you see "max" in the name of a PSU, it is a reference to the size of the pyrotechnic display it will put on when it dies, or to the number and expense of the other parts it will take with it when it goes. http://www.corsair.com/cinema/movie.aspx?id=622747 (love this link, including the "What an idiot" music)
If you intend to Crossfire two video cards on the mobo you have selected, the 650W Corsair linked by lothdk would be good. Antec, Seasonic, PC Power & Cooling, and Enermax also make quality PSUs. If you will only run a single video card, 500W-550W is plenty.
If by efficiency you are referring to minimum power usage, check out Intel's offerings. They will be more expensive up front, but power usage is notably lower, e.g.: http://www.anandtech.com/bench/default.aspx?b=63&c=1
The Apevia case may look nice, but I'd be concerned about quality. The single Apevia case I bought some time ago was a brilliant design, fatally flawed by extremely flimsy materials, and a factory drone had run a screw through the power switch wires, shorting them out. I've also not been happy with Coolermaster cases, and no longer buy them. Even my RC-690 had untapped screw holes and minor fit issues. My next case will probably be an Antec 200 or 300. I like the bottom-mounted PSU, and my wife's (and another) Antec Solo are excellent, solid cases.