Actually, I havent made a decision yet. I keep going back and forth on it. My current bulb has around 2200 hours on it. It may be a bit dim, but not so much that it noticably detracts from the viewing experience. I won't know how dim it really is (or isn't) until a new bulb goes in. I've heard similar comments on bulb replacements or off-brand bulbs not lasting long, so I would definitely stick with a Yamaha replacement. Given that I still think the projector offers a very nice picture I've just never really felt that compelled to update the piece. I would have to go through the process of tearing down and installing a new ceiling mount along with the new projector, and have even had people tell me that the difference between 720p and 1080p isn't HUGE...nor as significant as going from 480p to 720p. I don't know...I've really been considering keeping it for another year or two. That being said, I also am hard pressed to put too much money into it...money that could go towards purchase of a new projector. I'm also sure I would be loving a new projector, and certainly wouldn't regret the purchase. It's likely I probably would even by saying "why did I wait so long"
At any rate, if you do get a bulb, that Apex Lamps company seems to offer the best price; $399. Yamaha sells them for $600, but then I talked to a local Yamaha dealer who said they could sell me one for $500. This was better, but still on the edge of a "better to put money into a new projector" conclusion. A price of $399 does get me closer to considering a new bulb. I still want to absolutely confirm that they are selling the actual Yamaha PJL-5015 replacement part though.
I guess I should make up my mind sometime soon. I'm curious what you may decide to do as well.