My house has above ground wiring. The thing about above ground wiring is it's a lot easier to replace if they get damaged, because you don't have to have your yard torn to pieces to get them fixed. 
Exactly right Stephen.
Gil, underground wires have their own problems, so, no, their not less prone to problems. They just have differenet ones. And no, above ground wires are not dangerous. They say taht the big transmission towers are what's dangerous.
Well the power, specifically, is less prone to outages, since there is pretty much nothing at all that can disturb it.
Oh yeah, I think i was thinking of the big transmission lines. I saw lots of those today 
Again, not true. As I said, underground wiring has its own set of problems.
Mike, don't know if you realize this, but for each branch you cut off of a tree, it will grow several more. There will never be a depletion of oxygen.