I have a hard time answering this question. I saw them all play, except Flores.
Each of the QB's (that I watched) was very good, but I'm not sure how to do this. If it's by Super Bowl wins, then the answer is Plunkett. If the answer is based on single season stats, the answer has to be Plunkett. If the answer is on comeback victories and excitement, it's got to be Stabler. If it's for an exciting passing style, it's got to be the Mad Bomber.
I voted for Stabler with the 1 Super Bowl victory, several AFC Championship games and the excitement of the 4th qtr comebacks. To me, he just oozed the Raider image wth his hard-partying lifestyle.