It was almost as if my powerbook knew it was being replaced.... The day after I got my new 15-inch MBP, the bottom RAM slot on my 1.67 powerbook (within the replacement serial number range, and with applecare still) failed. So, the PB is off the Apple for repair before being handed down or sold. Of course, the MBP did have the yellow cast at the bottom, but my spyder calibration seems to have taken care of it. Fingers crossed.