Ottawa ranks 18th (tied with Luxembourg)! See the survey results and the top 50 cities at
Personally, I've lived in several cities (Lake George, Oswego, Beijing, Shanghai, Los Alamos, Santa Fe, Atlanta, Kingston, and Ottawa, in that order) and I like Ottawa the best. The reasons? It has what I want out of a city (arts, night clubs, universities, etc.) and they tend to be close by-- I live in "centretown" and I can walk to almost everything cool. Also, it's very, very beautiful. The picture you see was taken recently on a bridge over the canal. On the downside, yes, it's colder than bathing in a tub of Slush Puppie every winter.
Canada did very well in general in the survey. Almost every major city in Canada is featured in the top 50.
Never underestimate the power of poutine.