I ran the cable through the driver's side because the car has a gap between the steering column's rear cover and the dashboard and I hid it there, over the steering column. From the cigarette lighter to there is secure and hidden too, so everything's tucked neat and clean and it doesn't interfere with the driving.
Since I have the camera on my side of the rearview mirror, I wrapped the rest of the cable behind the sun visor, leaving out only enough to connect to the camera. Simple, clean, easy and, on top of that, I have enough cable up there to take the camera with me outside the car if needed.