Pittsburgh, Pa.
Reported GDP in 2009: $103.5 billion
Reported GDP today: $111.6 billion
Unemployment: 7.4%
Population change 2000-10: -8.6%
Yes, the city's shrinking, but those who are staying are employed and generally happy about it. The University of Pittsburgh and its medical center still provide most of the job base and U.S. Steel(X_) and PPG Industries(PPG_) still give the cities ties to its industrial roots, but PNC Financial Services'(PNC_) growth and Google's(GOOG_) expanding presence are the biggest symbols of a continuing shift toward the tech sector that mixes new businesses with old stalwarts such as H.J. Heinz(HNZ_) and Dick's Sporting Goods(DKS_). There are now roughly 1,600 tech companies in Pittsburgh taking up space in former mills and industrial plants, and combined with championships for the Pittsburgh Steelers and Penguins in the past three years (a Major League Baseball team is rumored to call the city home as well), that's a lot for Pittsburgh to be proud of.

http://www.thestreet.com/story/11110098/10/10-cities-unaffected-by-a-bad-economy.html