The pollution radius for power plants isn't too bad, so you can have it relatively close to your population centers without making everyone sad. And don't go overboard on power lines, since electric power jumps from building to building, just make sure you've got one line going from the power plant to the city. In my case, I've got an industrial center around my power plant, so I've been able to eliminate most of my power lines except for the ones that go to my water facilities.