IMO, it is worth it. I also purchased the HD1000U w/Lamp warranty. This is my second projector. I had to replace the bulb on my first projector after <1000 hours. After replacement, I found myself limiting the usage of projector to save on bulb life, limiting it for movies and special sporting events. With my new projector and warranty, I will be spending a lot more time watching movies in sporting events in my theater.
I would check the verbiage on those warranties very closely. I am not familiar with the one you purchased but I've read the fine print in a couple of them. They did not cover the lamp if it exploded which both lamp failures I've had in ~2 1/2 years have been from them exploding. Some also only gave one replacement lamp in the duration of the warranty, etc. Read it closely.
I bought the 3 year lamp warranty with my Mits HD 1000 from ProjectorPeople .I asked the sales guy if he had heard anyone ever having a problem with claiming a damaged or burned bulb and he said no,the most they do is ask you to find a local service repair tech to look at it before they replace the lamp, but most of the time it is not worth the cost so they just replace the lamp.