Hammerer: I have had many problems at DSE but they have always replaced defective products. I always keep my receipts as it makes it much easier to get the problem resolved. Sometimes I've even got a newer model. Usually the failure is in the first year of use so an extended warranty is not much use.
I would consider buying an extended warranty for any item over $1,000 which would be expected to have a long life such as a TV. I wouldn't bother with, for example, a router which I'm going to replace every 2-3 years anyway.
Heh I don't think I've ever owned a tv more than 2 years :)