For me it would just be places I don't particularly like to be. Of which there are very few, but:
Florida
Tampa
Columbus
Anaheim
Boston
(and maaaaaaaaaaybe Dallas)
when I visit Edmonton and Calgary I'll decide if they're on that list or not I guess. But even still, I think I could have an enjoyable life making, at bare minimum, hundreds of thousands of dollars a year in any North American city.
If I had a full NMC and could choose my destination? Probably: Seattle, Vancouver, Denver, San Jose, Pittsburgh, Nashville. Could tolerate Chicago, Philly, Toronto, and most other places. Never been too keen on living in LA or NYC based on my own economic reality, but I've also never been a millionaire, so I think either could be be fun for a few years if I had lots and lots of money. As far as the truly huge cities go, Montreal probably tops my list.