That's what keeps me from going HD. The TV's fail at a ridiculous rate compared to CRT sets. I see people reporting 3-5 yrs. life all the time in Amazon reviews.
well, a lot of the failures are probably fixable, though.
my old HD bugged out after about 4 years last fall. it worked, but it would take several minutes to power on.
brought it to a TV repair shop, fixed a broken capacitor, and it was like new for far less than it would have cost to buy a new one.