My husband lived in Brazil for a few months last year while he was teaching there and enjoyed it. Brasilia had a nice charm to it, and was far less chaotic and more laid back compared to it's larger counterparts of Rio and Sao Paulo. Additionally, not having to shovel a certain four letter S word off the driveway in September is an added bonus.
In North America, I'd say either Vancouver or Los Angeles.
For a more adventurous taste, I'd even live in Cairo, Egypt. I have a strange thing for busy chaotic cities.