If they never have to provide service, the money is all profit. All of the providers, although some mark up more than others. I would prefer buying the warranty from the manufacturer.
I have read the pros and cons of paying extra for an extended warranty and have concluded the peace of mind of having one is worth it IF the cost and coverage period are reasonable. I also know the plans offered by Circuit City, Best Buy, etc. are a huge profit item for them. So I figure, if I could buy a plan directly from one of the insurance companies that actually furnishes the service call or product replacement for these retailers, I could avoid the extra markup tacked on by them. Does anyone know the names & contact info for any protection plan providers that would be independent of where I end up buying my new HDTV?