I just came across this post on AVS by Doug Blackburn, who is a very well respected calibrator. I thought some of you with new plasma TV's would benefit from his insight.
"You should run the pattern disc exactly Zero hours. There is NOTHING the disc does that helps anything. "Break-in" is sheer AVS hogwash. Simply use common sense for the first 100 hours or so: minimize programs with black bars (a movie now and then is no problem); avoid long sessions with stationary graphics on the screen (news channels, games, etc.). Use normal settings for the TV -- neither too bright or too dark. Nothing you do will prevent early will prevent burn-in... NOTHING. If you do something bad enough to cause burn-in it doesn't matter if the TV has 5 hours or 5000 hours on it (with anal use of the burn-in disc)... you are still going to have a burned-in TV on your hands. Nothing you do early on will stop image retention either. Your TV will ALWAYS be susceptible to burn-in and image retention. It is a plasma and current plasma technology has not eliminated these undesirable characteristics and no break-in disc will EVER change that in ANY way.
That said, the phosphors in your plasma TV will change somewhat during the first 100-200 hours, but they are going to change exactly the same way no matter what means you use to put 100-200 hours on the panel. You can simply watch TV like a normal person (avoiding over-doing any of the things mentioned above), or you can uselessly rack up 100-200 hours on the TV and DVD player with a break-in disc and end up at EXACTLY the same place either way. "Break-in" discs are AVS paranoia/hysteria run amok."
He is absolutely right about the hype built up about burn in discs; I got sucked in, and was extremely worried, I just wish I got his opinion before wasting at least 100 hours running said disc. Not only because of its limited or zero effect, but also because it racked up my hydro bill an unbelievable amount when I was running my plasma TV for days on end.