3. Sergeant Doakes (Seasons One & Two)
Unlike the others on this list Doakes was not a villain, in fact he was perhaps the best cop in the whole show and that was his problem. Through out Season One Doakes was hot on Dexters trail, feeling freaked out by not only Dexters presence but also by his comfortable nature around all things murder related. The wise cracking detective began to put the pieces together in Season Two and Dexter couldnt be having that. Inspired by his counsellor Lila Dexter decided to set Doakes up for all his crimes and kill two birds with one stone. This plan ultimately led to disaster when Dexter had to keep Doakes locked up in a cabin in the woods. Then just when it looked like Doakes had managed to convince Dexter into confessing to a life time worth of crime, Lila came along and blew him and the cabin into oblivion.
Defining Moment: Doakes is one of the show's best loved characters and there is some great video compilations of his best bits online. My personal favourite is his 'Surprise, Mother F*cker!' confrontation with Dexter at the docks.