[Arran]

I have also heard of people using welding wire, such as for a MIG welder, for an antenna, I'm not sure how long it will last but it is typically copper plated. The difference is that it is MUCH cheaper then solid copper wire of the same gauge. In the past I had a long length of 14 gauge house wire that I used for an antenna, it was left over from when they replaced the dust collector in one of my shop classes in high school, so I asked about it, I think it was 40 or 50 feet long.
Rich is right about the power line grounds, it does eventually ground to earth, but it's also running parallel to the hot and neutral lines in the walls, which could be radiating RF trash into it through induction. There is a lot of debate about how to create a proper antenna ground, but no where did I hear or read about using the electrical ground for the antenna ground being the best way, though there is no harm in trying.
Regards
Arran