I took out $0 for my undergrad and $70K for law school. We hope to have enough to pay for our kids undergrad at state schools (or equivalent cost) and we have no idea what we'll do for their grad school. One thing I learned from taking out $70K is that those kids who have their grad school paid for (by any means), are 10 years ahead of those who have $70K debt!
If you come out of grad school with little or no debt, you can immediately start saving for a house/condo -- which puts you on a whole different path financially when you want to have kids, etc.
We probably need to be saving more, but there is only so much $$ to go around. Like many people -- we'll deal with some problems when they come (i.e. grad school tuition).