Power conditioners .... improve VIDEO?

I heard recently that certain power conditioners can actually improve video in home theater. I have a JVC projector, Toshiba HD DVD, Verizon FIOS and Meridian G68 AV processor.

Anyone have personal experience with this?

Well I hope it works for me as I just bought adcom p/c in the hope for better video image and less noise.I have heard different opinions on the audio side however,I hope for the best.I will change the Power cord on my Sony HD TV also.
I added a Monster HTS2000 - really basic unit a couple years back and noted much more improvement in video on my Pioneer Elite 58" than audio. Not much cost, demonstrable improvement.
It's pretty shocking until you see it; improvements in image depth, noise, colors and black levels. The level of improvement depends on how bad the signal is in the first place, but improvements are obvious even with high def media. If you can swing it, the Transparent PowerIsolator Reference is brilliant.