4. John Cena
WWE.comIf Punk were to return soon, another series of matches with John Cena would always be in the pipeline. The two have shared some epic encounters over the WWE Championship and their bout at Money in the Bank in 2011 will go down as one of the most famous in WWE history. Despite several matches, what leaves this rivalry up in the air is the lack of clean finishes when the two superstars collide. Their match at Money in the Bank had an interference from John Laurinaitis, at the following Summerslam Triple H made a refereeing error and at Night of Champions 2012 their title match ended in a draw. For this reason and the fact that Cena is now champion, CM Punk could be booked to feud with Cena to prove he is the top guy.