I want one, but can't justify it. Probably be into it around 10K installed, maybe more. We've only had one multi-day outage in the 12 years we've lived here, because our wiring is all underground and it took a century level storm to wipe it out. We get occasional outages of a few minutes to a couple hours in the winter if a tree hits a power line somewhere in the nearby above-ground grid, but that's about it. I'd still love to be the only guy in the neighborhood all lit up when everyone else goes dark :). To be fair, I'd actually be #2 now, guy a few houses up the street is that beacon of light now. But still.
When we were shopping for houses out in the sticks, I had that generator budgeted right into the price of the house. If I got a multi-day outage very year, it's a no brainer.