After narrowing it down Im going to go with Punk , Sheamus or Orton .
Here are the big contenders
John Cena :Will be feuding with the Rock at mania in a match so big that it doesnt need to have the title involved . I see Rock being a suprise entrant in the rumble and eliminating Cena . The two of them will be involved in the elimination chamber with neither winning and then they will face off in the m.e of wrestlemania.
Orton : He has to be in the title match at wm . He is the face of the sd brand and I know he may not be in most of the iwcs eyes but to the casual fan he is the best in the business . He hasnt been in the title match at wm in two years and three years without out him seems unlikely unless Jericho returns and has a match with him at mania . Another interesting match would see Orton win the rumble and choose to face Henry only for Henry to be cashed in on by Bryan after the chamber match so that he can face Orton at wm .
My pick to win the rumble
Sheamus :If the so called rumours of Sheamus being in the title match at mania are true then this would be the easiest way to get him in the match . Hes young and it seems like vince is going to really invest in him so I could see it happening . But the only way i think it could happen is if Jericho came back and feuded with Orton till mania because as I said above , Orton will be in the title match UNLESS HE HAS JERICHO TO FACE and I doubt they will do Sheamus / Orton again .
Jericho :Its been a a huge two years since someone has returned and won the rumble and we all know thats far to long

The man I could see making a comeback would be Jericho . He is the best guy to never win a rumble and he should be feuding with Orton when he returns so why not have Orton win the title from Henry at the chamber and face Jericho at wm.
CM Punk :Enough about the world heavyweight championship . Id like to see the winner go after the wwe title and in my eyes punk is the only guy credible enough thats isnt on the smackdown roster to go for it .
Lets say we have Rock/Cena and Orton/Bryan then we still need a wwe title match . He has been the real star of 2011 and the perfect thing for him would be to face Del Rio at wm with HHH in his corner and Laurinitis or Vince in Del Rios corner .
Other guys with a chance .
Del Rio
Two rumbles in a row . Unlikely
Mark Henry
I reckon Henry holds the belt till the rumble so he wont be in the match .
HHH
Surely he doesnt need to win the rumble to make an impact at wm .
Miz
He was there last year , dont see that happening again .
Undertaker
:no:
Barrett
On current booking not credible enough . Maybe in 2013