The Institute for Health Metrics and Evaluation, a public health researcher at the University of Washington, has crunched life expectancy numbers for every U.S. country. For men, Fairfax County, Va., is best with a life expectancy of 81.1, vs. 75.6, the 2007 male national average. For women, it's Collier County, Fla., at 86. In more than 300 counties, life expectancy for women dropped.