My 55" xbr8 started demonstrating the same problem shown in Wally 1912's photos above. This was in Nov 2011 after 2.5 years of flawless play. The vertical bands would vary in location on the screen, width of the bands, full length or partial way down the screen and color of the bands depending on the content on the screen. All the above issues will change instantly from one scene to another. Interestingly, on mostly white content, the bands will disappear and there is the incredible xbr8 picture of old, the content changes and again the screen is a mess.
I had the Sony tech in twice to work on the set, to his credit, he spent +/- 6 hours working on the tv, checked entire power supply circut and every board in the unit, changed out the T-Con board to no avail. He concluded this was a failure of the panel. Price for new xbr8 panel...$5,999!
This was a serious eye opener for me. I assumed, naively, these sets would last like the tube tv's I grew up with, 20+ years and still going strong! I assumed when purchasing this unit that it had the same quality as tv's in the past; and costing many times more, I thought this set would be bullet proof. Clearly, not the case; and it's not just Sony, a bit of research reveals that the defect/failure rates on these new panels is through the roof for most manufactures.
For the first time ever when buying the xbr8, I swallowed hard, and bought the extended warranty; of course it was also the first time I paid $5k for a tv so thought of it as buying peace of mind. I can honestly say, lesson learned; I will never buy another expensive electronic product without the maximum extended warranty. I was refunded the full purchase price for what amounted to a 10% investment. I am as disappointed as I could be in this failure, I thought the xbr8 was the perfect tv (rgb led, local dimming, ect) and anticipated it would last many, many years. If extended warranties were not available, I would not buy another premimum tv.