I'm considering purchasing of line conditioner. I currently own Monster Cable surge protector and in my understanding it only protects the equipment against power surges, but it does not improve picture or sound. Manufacturers of expensive line conditioners like Monster Cable or Panamax claim that their products improve home theater performance. I own Denon 4802 receiver, Denon 2800 DVD player, Sony 65XBR10W HDTV, Echostar 6000 high definition satellite receiver and Diva 6.1 speakers. I'd like to know if spending close to $400 on line conditioner is going to improve performance of my equipment significantly, or is it marketing trick or maybe the improvements are visible only on high-end equipment and differences are only very subtle, visible only to real audiophiles?