I have the original bulb (my TV will be 5 years old in March).
I'm tempted to buy a backup bulb - my sales contract says Tweeter will sell me 1 bulb at cost within the 5-year service contract; but Internet prices are only $150 or so for the XL 2000U bulb, e.g.:http://www.lcdanddlpsource.com/sony-...FQNegQodLkHOJQ
I'm glad I got the extended warranty. A couple months ago they replaced the light engine, a $1200 part/job. A year or so ago I had something else replaced that was worth a few hundred dollars, and had a previous service call to line up the LCD panels. I've gotten my money's worth from the extended warranty several times over.
If something goes wrong with it outside of warranty, other than a bad bulb, I can't see repairing it; it would be better to buy a new TV w/warranty, etc., IMO.
But it's been a good TV (other than the poor black levels).