Sorry for not replying sooner, but I have refrained from registering, and posting on this board, for fear of jinxing myself!
My 4663 did the exact same thing when it was 2-3 weeks old. I had to do the same as you (shut down at surge protector), wait a few minutes then restart. This was mid January, and it's never done it since.
I have turned the set on a few times (maybe 6 total), and had a few thin red horizonal lines, and square outlines all over the screen. It's like I'm seeing the outlines of the mirrors. When this happens I just shut the set off, wait the few minutes for the fans to shut down, then restart. It's never come back two starts in a row.
Other than that it's run flawlessly. No screen smudges, no color wheel noises, just a great picture.
Hope you have better luck with your new set. BTW, mines a Nov/04 build.