10. San Diego, CA
No wonder we start in San Diego. The beachy city has a higher percent of people walking or biking to work, and a lower percentage of smokers - I should know, I've tried buying cigarettes here to much judgement. Also, 23.5% of the city land area is dedicated parkland, more than double of the ACSM's target goal of 10.6%
[Photo via @lukasvarez]