I believe that "Fine Woodworking" or "Fine Homebuilding" magazine addressed the issue of static in PVC dust collection systems. The final answer was that the NFPA did not consider the issue to be a risk until you reached CFM levels far above anything a household shop would be able to generate.
As for the wiring, not only do I lean toward EMT (solvent resistance, won't sag over time), but I suggest the use of minerlac hangers (as opposed to bending offsets), and supporting the pipe twice as much as usual.
The clearance that the hangers will give the pipe will prevent dust from collecting there. The additional hangers are for supporting the rags, clamps, etc. that are sure to be hung from the EMT.
Another suggestion: make liberal use of "drop cords." These are cord caps hung from a box on the ceiling, using the rubber-grommet strain relief bushings and short lengths of SO cord.
