I'm running Cat6 through out the house and have all but one room done. Due to how the house is built I don't have access to the headers above three of the walls. I can access the same spot where the phone line drops, but this is about 4-5 inches away from the power line drop.
It's very tempting to just run the cat6 with the phone line and be done, but that would put it parallel to the power line for about 8 feet, separated by 4-5 inches. So far I've been able to avoid that in every other room.
Is that just asking for trouble with interference?