This is a detailed part (due to the tooth profiles) so use your smallest nozzle.
Print in PLA, it will last a lot longer due to being harder than ABS.
Set 0 extra shells (skeinforge)/ 1 perimeter (slic3r) because you can get hollow teeth with extra shells/perimeters.
Use 80-90% infill. I've already removed lots of plastic, what's left is what's needed. If your infill is too low, the most likely failure is the nut trap in the small gear will break.
You'll need really good cooling to do the base of the small gear properly. When the large gear is finished, crank your fan up to max, perhaps convince your slicer to slow it down a little too.