As I recall, there were only 2 that took the top spot... Carrie Underwood and Scotty McCreery. However there have been several others who didn't win, but who went on to do fairly well in the country music scene. Josh Gracin, and Kellie Pickler come to mind, but there were probably a few others as well.
The top two country singers who won the American Idol were Carrie Underwood and Scotty McCreery. Some of the artist became famous for performing well at the country music scene. These included Josh Gracin and Kellie Pickler.