When Guru3D did their GeForce GTX 580 3-way SLI review they measured a power consumption for just the three graphics cards under full stress to be 736 Watts. When they ran FurMark the power consumption of just the cards jumped to above 900 Watts.
The graphics cards obtain all of their power from the +12 Volt rails. There is a power VRM circuit on each graphics card that converts the +12 Volts down to the voltage required by the GPU (I thought it was something like 1.05V when running a 3D app and 0.98V when idle or running in 2D).
A realistic current draw, for each GTX 580, is 20 Amps from the +12 Volt rail(s) for a total of 60 Amps for all three graphics cards at full load.
If you were to run FurMark GPU stress testing the current draw may jump up to 28 Amps for each GTX 580 for a total of 84 Amps for all three graphics cards at full load.
The ENERMAX MAXREVO 1350W (EMR1350EWT), with its combined +12 Volt continuous current rating of 112 Amps, is more than sufficient to power your system with all of the components you've listed.