Epson provides a two year parts and labor warranty on the Home Cinema 8500UB. Epson's almost identical Pro Cinema 9500UB, offers a three year warranty.
With the Epson 8500UB, you also get a two year replacement program, which essentially means that if you have a problem covered by warranty, Epson will overnight you a replacement from their replacement fleet, and you just send your old one back. Epson pays all freight.
That's about as good as a two year warranty can get. If you spring the extra for the Pro Cinema 9500UB, not only does the warranty go out three years, but so does the replacement program.
The most common warranty for 1080p projectors is two years, but there are some one year warranties, and a few projectors with three.
Of the popular competition, The BenQ W6000, several Optoma projectors, and the Panasonic PT-AE4000 have one year warranties. The Mitsubishi projectors have two year warranties as does the InFocus IN83.The Sanyo PLV-Z3000 offers a three year warranty, along with the higher end Optoma's and the BenQ W20000. JVC and Sony primarily provide two year warranties.
While not the longest warranty out there, the Home Cinema 8500UB's warranty is above average thanks to the replacement program. The Pro Cinema 9500 UB's longer three year warranty, with replacement program, has to be considered as good as they come, at least in under $10,000 projectors.