Struggles with heroin plagued Reginald "Bubbles" Cousins (Andre Royo) throughout the course of The Wire's five seasons. Unlike other smack enthusiasts to grace our list, Bubbles didn't juggle his addiction with a traditional 9 to 5, but instead used his time and knowledge of his city's dealers to serve as an informant to the Baltimore police. But just because he was a rat doesn't mean he wasn't a good dude; Royo's character was one of the most well-meaning of the bunch, doing his best to pull those he cared about out of funks that he himself was barely able to rise above.