My original goal, set way back in 1999 at the age of 29, was $1M, and no mortgage. I had finally paid off the bills from a bad divorce in 1998, and '99 was the year I really started getting my financial act back together. Refinanced my condo to a lower rate, was able to qualify for 0.9% financing on a new '00 Intrepid...thought I had it made! I finished out 1999 owing around $73K on the condo, and I had about $40K in "investments" (after tax + 401k + IRA), and another ~$17K in checking/savings/savings bonds, or about $57K total. Back then, $1M seemed like a lot of money, and a long ways off, and with a mortgage out of the way, seemed like it would go a really long way.
Well, here it is, early 2017 and I'll be 47 in April. I'm up to around $1.2M in "investments", and another $14K in checking/savings/bonds (for some reason, I mentally keep the two separate...I think it's partly because the savings bonds were something my Mom and other relatives got for me, so I don't consider them "earned"). Condo is long gone, but now I'm in a house that has around $119K left on the mortgage. The Intrepid has probably been recycled into a new Prius or something like that, but I currently have no car payment.
Adjusting for inflation, I think my original goal would come out to around $1.5M, plus no mortgage, and I think I'd be happy with that. I'm planning on buying another house just before I retire though, and my tastes in homes seems to be all over the map, price wise. So now I've got sort of a floating goal of roughly $2.3M, which is a combination of investments + home equity + mortgage. I came about that figure because, in looking at houses, the most expensive one I've seen that I've really liked was around $800K.
That's probably some sloppy math, but that's what I'm sticking to, for now!