Actually, extended warranty is not all that bad, but it depends of what products you're buying it for. I would buy exteded warranty on big purchases, one is because it would cost you just as much for a ONE TIME service on that TV set. Seconely, depends on the warranty, some of them cover maintenance, which is needed for a projection TV.
Most of you know by now that I used to work at the GG, and I sold and bought warranty. I have used warranty on numerous of products, and the best warranty to get is the replacement service. (This is kinda wrong, but I can think of all kind of excuses to get me a new DVD player two years after the original purchase). So depends on what is covered on the warranty, it's a safe bet to get it on shiets that you value.
EDIT: And I hope you're smart enough to know what products not to buy warranty on. 😉