Pittsburgh remains most livable city in the US

According to the 2011 Liveability Ranking and Overview by the Economist Intelligence Unit.

http://www.reuters.com/article/2011/02/21/us-cities-liveable-idUSTRE71K0NS20110221?pageNumber=1

http://www.huffingtonpost.com/2011/02/21/worlds-most-liveable-cities_n_825964.html

http://www.post-gazette.com/pg/11053/1127102-53.stm