Oh god, that's what we all wait for, isn't it? Followed by retirement...
My wife and I have friends who are our age (both 40), and they had their kids young. They have just become empty-nesters.
Haha. I said both kids were gone, but actually, one has moved back in temporarily. She got divorced in June. So she is with us till she gets her own place. I know that will be soon though, she's working on financing for the house she wants.