John Cena held the company far longer than Austin & Rock did.
Hogan was WAY bigger and more loved in the 80's than he was in the 90's.Have to go with Hogan here, just because he was loved by so many in the 90s. It was devastating to many when he turned his back on the fans and joined the NWO...one of the most notable events in wrestling history which, by itself, tells more than enough when answering a question like this.
And, his feud with Slaughter was amazing. It created the American Hero in sports (entertainment or competitive), and the timing was perfect.
Has to be Hulk.