That certainly made sense when home mortgage interest rates were way up around 12-14% like they were when I bought my first house. But at 2.75%, there's not much sense in paying it off early if there's the possibility of having to finance anything else down the road... such as children's college education, new car, new garage, etc. If cash is flush, and there's no need for future financing, then certainly it makes sense to pay if off. However, one good thing about having a low-interest mortgage is that it helps your credit score.
Also, keep in mind the interest on a mortgage is tax deductible, but the car loan interest is not.