I could see a few possible scenarios playing out tonight on RAW setting up for Cena's first title defense at Over the Limit.
Alberto Del Rio - there were rumors of him feuding with Cena over either the WHC or WWE title this summer and now that Cena has the WWE title, we might see that match for SummerSlam. the rumor was that it would be a summer feud so maybe they dont start yet.
CM Punk - the most unlikely of any top contenders for the title. coming off a string of losses to Randy Orton and seemingly on his way out after his current contract expires. however the whole deal with Punk was that he was mad that he wasnt getting pushed and thats why he wants out (along with burnout). Maybe give him a shot and a run at with the title, off of house shows for a little while (unlikely as he is one of the tip heels in the business) but this could solve his contract issue. also, i think he might start a feud with Mason Ryan tonight or have Nexus lock onto their next target...Evan Bourne? Punk did attack him and put him on the shelf just before Punk started his stint as commentator.
John Morrison/R-Truth - highly unlikely as the two will feud with each other, i could see both of them making their cases for the number 1 contender spot as in JoMo's case he wasnt pinned in the cage last night and in Truth's case, the WWE could have a program where 2 former friends collide in Cena/Truth. if you remember, the two teamed a few times while Cena was feuding with the original Nexus.
Miz - most likely of contenders. with his rematch clause being invoked tonight, we might not see that match considering he's using his clause tonight. with it being The Rock's birthday bash tonight, i could see the Rock costing Cena the championship but since its Super Cena its not likely. possibly just a run in after the match.
After going thru the top contenders, lets look at the rest of the RAW roster.
Big Show - unlikely candidate at he is currently tag champs with Kane
Chris Masters - i see him in the running for a possible US title contendership
Curt Hawkins - completely lost in the RAW roster shuffle. its either Superstars, a complete overhaul of his character (reunion with Ryder?) or fired.
David Hart Smith - same as Hawkins. trying to pursuit MMA so he might be on his way out
David Otunga - still involved with Nexus. maybe a little while longer and he could be ready for US contendership but he needs work
Dolph Ziggler - the most likely of this list. he's a former tag champ, intercontinental champ, and even WH champ. i see him being the next contender for the US title tho or starting a feud with Bourne if Punk and Nexus dont. especially after last weeks beatdown.
Drew McIntyre - he would be a good contender. descent in the ring/mic. he could use a mid card feud or even a US title run first tho. maybe even a face turn
Evan Bourne - it seemed like the WWE was putting stock into him before he got injured when Cena stepped up to the big dogs in WWE saying this guy had talent. and he does! hopefully he gets a run at the US title soon because i dont see a WWE title in his future for some time (if ever)
Goldust - i still believe he is injured and hes a lower/low mid card guy. there to job to other guys.
Jack Swagger - unfortunately still in that stupid program with Cole/Lawler/JR. he could do good things with cole. get him away from the announcers tho. let cole manage him AND ONLY MANAGE HIM and we could see a US title run. possibly a WWE title shot.
JTG - he was barely even used on SmackDown! doubtful for the ME picture on RAW
Kofi Kingston - current US champion. cant say its never happened tho. Jeff Hardy vs Randy Orton at Royal Rumble a few years back. Hardy was IC champ and Orton was WWE champ. but he's a face, shudnt be feuding with Cena.
Mason Ryan - not ready for ME and still with Nexus (maybe)
Michael McGillicutty - same as Mason Ryan
Primo - nowhere near ME level. not even near US title level
Rey Mysterio - maybe. i could see in an upper mid card role tho. like what cena had while orton was fighting for the championship and vice versa.
Santino Marella - i believe he's still in a tag team with Kozlov and i dont wanna say it cant happen as he was one of the last superstars in the RR. never say never in pro wrestling...i mean entertainment!
Skip Sheffield - still injured i believe. he would be a good guy for the ME tho. work on his mic skills as he hasnt been around for a while and i dont remember his work. feud with Nexus?
Triple H - i dont think we'll see Triple H around until possibly SummerSlam. hopefully he doesnt challenge Undertaker at WM again...but thats not the point.
Tyler Reks - US title would be great for this guy
Vladimir Kozlov - same as Santino
Zack Ryder - it seems like WWE really hates this guy. hes great. give him a US title shot. if not that just a normal feud. but make him credible. WWE is missing out on a great talent.
While I was writing the possibilities for the above superstars, I thought maybe they could bring back the "WWE Title Virgins Battle Royal" that Jesse "The Body" Ventura invoked last year when he was Guest GM. Get all the guys who havent won the right to hold the title and put them into a battle royal. Ironically, thats how Sheamus won the title from...you guessed it...John Cena! This would be great for guys like Bourne, McIntyre, Kofi, Ryder, and other guys. It will be interesting to see if they let Ziggler or Swagger in as they have held WHC gold.