Right now, I'd go with Bo by a good bit. However, I'd like to see how time and a little history treats Cam's stint/contribution at Auburn. Who knows right now? Will Newton come back and make tons of appearances? Will he pimp AU all through his career? Will he become a huge success both on the field and commercially? Will he be thought of as one of the greatest to play the college game later on in polls and roundtable discussions? I realize a lot of that doesn't have a direct affect on Auburn but it may change how we view him in the years to come.
This is as much it as anything. Ask me again in 20 years which one had more of an impact on Auburn, and if Cam does not show himself as an Auburn man, then maybe I change my opinion.
But right now, if you say Bo Jackson, everyone knows Bo, and all his accomplishments, and about his NFL/MLB careers... but not many people outside the SEC can tell you who he played for. Earlier in the season last year, when Cam was first making a name for himself, someone I work with made a comment about the best player AU has ever had. I corrected him "Second to Bo." And he said "I thought Bo Jackson played at Georgia. I had no idea he went to Auburn.."
EVERYBODY knows who Cam played for. And he won the national Championship for Auburn. AUBURN.
So to answer the question honestly, it has to be Cam. From our insider perspective, yes, Bo IS Auburn - but not in the eyes of anyone who is not intimately familiar with the Auburn program or is a long time fan of SEC football.