Many, many places in Europe, of course.

In North America, it's harder:

Vancouver, B.C., would be do-able, but you'd have to choose carefully. Montreal, Quebec, is much better, in most places within city boundaries. New York City, Boston/Cambridge of course. I think Portland would be pretty good in many areas, but I have found Seattle to be very car-centered and divided by deep highways. I don't know the city all that well though. I don't know a lot about Winnipeg, Edmonton, and Calgary, but the outlook seems grim to me. Toronto? I guess.

San Francisco, maybe? But it's steep.

Following Kunstler (The Long Emergency), small, former industrial towns (New England style) are best for the long term, if one lives in the centre. However considering the standard of health care that is required to keep so many of us alive, it would make it difficult in smaller towns with no high-level medical infrastructure.