In the projector industry, projectors competitive with the Dell in performance probably average about a 2 year warranty. There are some brands, like InFocus with one year, Epson, by comparison has two years. Optoma's competing model as well as units from Panasonic have 3 year warranties.
However, Dell's price on the 2400MP is pretty agressive. As a result, you can afford to add on one of Dell's extended warranties, to beef up the total warranty package.
These are the options Dell offers: You can buy a 2nd and 3rd year Advanced Exchange warranty, or even one that adds four years for 5 years worth of coverage.
If you are even more trouble prone/careless, you can choose Dell's Complete Care Service option which covers accidental damage, for 1, 3, or 5 years.
To give you an idea of pricing, here are a couple:
3 year extended with Advanced Exchange with CompleteCare: (total of 3 year's coverage): $338
3 year extended with Advanced Exchange: (total of 3 years coverage) $169.
The bottom line here, is that for an extra $169, you can have a nice 3 year warranty instead of just one. Considering the high cost of repairing broken projectors, it's a good idea.