How much space between cables is enough?


I understand that proximity between power cables and interconnects or power cables and power cables is a problem, but is there a rule of thumb as to how much space is required to NOT be a problem. 1/2", 1", 6"? Also, are all cables the same? I would assume that the higher the current, the more isolation, but belief and reality are seldom the same.
128x128tony1954
I tried the rubber band thing for about a decade.  I stopped using it, but later found out my cables were probably picking up ripples in space/time from merging neutron stars and black holes.  Yeah, this was before LIGO.  My system was way too analytical back then.
My AES3,  ethernet and power cable all run down one of the legs on my speakers stands. They are hidden in the back attached with velcro and are about a couple of millimeters apart. Once they get to the floor they are all together velcroed then they separate at the rack, power to the surge power conditioner,  ethernet to my netgear switch and AES3 to the streamer. My cables are either touching or within a few millimeters. 
Do people really want to be in the room with cables floating in the air hanging on fishing lines?
tony1954,

"Do I coil it around the water tank clockwise or counter clockwise?"

It will heavily depend on the side of the water tank you will be doing it from.