Permanently? I think in that case I'll stick with where I'm right now. It's the right mixture of peace, safety, action and a good climate.
However, I wouldn't mind living in a really big city for a while. I'm not thinking about the third world, or cities that change completely over the course of two years (like Hong Kong or any big cities in Asia), but cities who've had a history of being big and important, like London, New York City, Moscow or Paris. However, I doubt I'd last more than 2 years in a place like that. I'd also want to have the time to explore the city rather than sweating to work and back and not getting to do anything else the entire day.
Peachy