I haven't had negative equity in any of my homes since I bought my first in 1977. My current home's equity was (at least on paper) very high just a few years ago but it dropped quite a bit in the current economy. Even at it's lowest point in the last few years, I had enough equity in my home to be able to sell it and pay cash for an above average house just about anywhere in the US and probably a mansion in most places.
Of course no one can know the true equity in their home until they actually find a buyer and sell it.
I plan to retire in less than 10 years and when I retire my plan is to sell the house and pay cash for something smaller. It would be nice if there was enough left over to tuck away in the bank to add to my retirement nest egg.
I bought my first house in 1977, sold it 3 years later for 2X what I paid for it. Kept my 2nd house for 10 years then sold it for 2X what I paid for it. Bought our current house 20 years ago and could have sold it about 5 years ago for 4X what I paid for it but it's currently only valued at a little over 2X what I paid for it.
Here's a pic of my current house: