One thing I don't understand is the logic of having a 30 year mortgage on a home and filling up savings accounts for kids college and retirement with that kind of dough. If I had all that income, I'd try to pay off my house ASAP. In the end, it would leave you with a lot more wealth and savings on interest.
If your 30-year mortgage is at 4.5% and you make a decent living, with tax deductions you are paying only 3% to 3.5% interest on that loan. Investments should be able to beat that most years.
That's the rational thing to do, but I'm with King on this one. The interest savings aren't that big given their incomes and there's a lot of pleasure derived from being debt free.
Of course they shouldn't have a massive mortgage either.