I doubt he'll win another world title for quite awhile. After having such a long title reign, I don't see them putting another one on him again too soon, if ever (if/when they finally do, it'll be the WHC, not the WWE Title.) He might challenge for the belt afterwards, of course. If Wrestlemania ends up being either Cena-Rock or Punk-Cena-Rock for the WWE Title (Cena would be walking out as champion in both scenarios), I could see them doing one last Cena-Punk match in April just to have that last final blowoff match between them, and to see Cena finally defeat Punk, but that would be it for awhile. Punk would continue to be in some of the main storylines, but not in the main event. What's funny is that that's the exact position he's been in on the card for the majority of his title reign anyway. He's only just began actually main eventing PPVs just recently in the fall.