http://www.biggerpockets.com/forums/99/topics/1535...
According to USA Today...below are the top 10 rental real estate markets:
(They looked at annual gross rental yields from RealtyTrac as their basis)
10. Hernando County, Florida
Annual gross rental yield: 17.29%Vacancy Rate: 5.1%9. Pasco County, Florida
Annual gross rental yield: 17.30%Vacancy Rate: 8.9%8. Columbia County, Florida
Annual gross rental yield: 18.42%Vacancy Rate: 11.3%7. Wayne County, Michigan
Annual gross rental yield: 19.88%Vacancy Rate: 8.9%6. Spalding County, Georgia
Annual gross rental yield: 20.35%Vacancy Rate: 12.3%5. Putnam County, Florida
Annual gross rental yield: 22.63%Vacancy Rate: 6.3%4. Howard County, Indiana
Annual gross rental yield: 24%Vacancy Rate: 6.6%3. Duplin County, North Carolina
Annual gross rental yield: 24.4%Vacancy Rate: 8.8%2. Clayton County, Georgia
Annual gross rental yield: 26.88%Vacancy Rate: 16.9%1. Edgecombe County, North Carolina
Annual gross rental yield: 41.57%Vacancy Rate: 11.1%