I bought extended warranties for my two XBR TVs. At the time I got pretty much the same deal you did, so it was a no brainer. The only problem I have is the TVs won't break. I've never had to use the warranties. I've had the TVs for over 7yrs without a single problem. I would like to buy a new, slimmer, higher definition TV, but can't justify it. Say what you will, but I've never had a problem with the Sony TVs I have or the ones I've bought for family members. Not having to use a warranty is a waste of money, but I can't complain.
I also bought a Sony STR-D5300 receiver at the same time. It had a firmware issue I noticed within a few weeks. I called Sony, it was a known issue. They sent a replacement the next day along with a return label for the defective unit. You can't ask for better service than that. No problems since.