Well, Apple has my 12-in PB. It had developed a shadow, or dark spot (quite small, but noticeable) in the lower left corner. We were going to a mall with an Apple Store today, so I took it along and showed the genius bar guy that, along with a ripple in the upper left corner that occurs when the machine is touched at that point on the outside.
Sniff. My PB has gone to be fixed. I'm suffering withdrawal.
But -- all I can say is I sure am glad I purchased AppleCare, b/c the machine came out of warranty about 7 weeks ago. That dark spot just developed in the last week or so.
Of course, I'm afraid they'll ruin it fixing the LCD screen...