if you don't want to get too crazy with the install, they make wireless/portable systems, and usually you can adjust or add transmitters for larger yards.
one of my friends has a wireless system for their doberman, and they love it.
one of my neighbors has a wired system, and there's been a number of breaks in the line over the years. one of their labs found a break last year and was killed by a car.
I guess it depends on your dog, too. The lab that was killed obviously had no fear of the fence if he was close enough to find a break.
the doberman won't even get into my friend's car if it's too far down in the driveway because his collar will beep slightly.