Alaska might end up seasonally uninhabitable -- they have periods of the year where the sun doesn't set, with increased greenhouse gases in the area it could become intensely hot for periods of the year. Combine that with periodic ozone holes that appear over arctic areas and it might be just as nasty as areas we worry over today...

Areas near large bodies of stable fresh water are likely going to be livable for the longest periods as the planet rapidly shifts away from what we humans need.