I bought the extended warranty with my Samsung DLP when I first got it two years ago. I figured, if something DID break, it would be pricey. The fact that it included the lamp just sealed the deal. Fortunately, I have had zero problems with my TV. Now, shortly before the 5 year mark, I will definitely call and say that my TV "just isnt as bright as it used to be".
My dad bought a Samsung DLP a little over a year ago, and they had to put in a new light engine this week. Good thing he bought the warranty...the installer said the light engine would have run over $2000 + labor.