Assuming something could wipe out Canada (really big country)... I have lived and worked in a lot of places. I would consider the US, very friendly country plus if we all moved south the democrats would get 30 million new voters and shift a lot of states blue. The UK is great but the food (outside of the curry) is just so bad. Japan is a huge rat race and not welcoming of foreigners (yes I worked there for a while... there are many places there that only allow Japanese people only in, restaurants, bars, etc..) otherwise nice. I guess my question is how badly destroyed, because it would have to be really bad for me to want to move.
Second thought, South Korea, great food, welcoming of foreigners, and PSY!