WWE Championship - Retirement Match
Triple H(c) vs Shawn Michaels
HHH wins the title back at the Royal Rumble. HBK then goes on and wins the Elimination Chamber Match at No Way Out/Elimination Chamber, well HHH retains. Within the next few weeks, Hunter tries to convince Shawn to go Smackdown, like he did with Batista. Michaels eventually says he is going to retire and wants to face Hunter at Mania. However, rather then showing respect HHH gets angry and pedigrees Shawn. This leads to them Heel vs Face into Mania. Then, HBK wins the match after 30 minutes of back and forth action between the two. Post-match, Hunter and HBK both celebrate, and then with HBK retired they would end up going into a tournament to determine the new champion starting the next night. (Also, I think if WWE manages to keep the whole guest host concept HBK could become the new GM).
World Heavyweight Championship
CM Punk(c) vs Batista
This rivalry leads up with Punk becoming the new champ at "TLC" in December, and Undertaker eventually getting taken out of the picture (Will explain how later...). Batista is the last man in the Royal Rumble with Shawn Michaels, and is eventually eliminated by HBK. However, the next month at No Way Out, as CM Punk retains his title Batista wins a tournament to get him a World Title shot at Mania. The next week Punk begins to accuse Batista of getting his big muscles from steroids... Batista is enraged, and confronts Punk. This goes on for weeks, and eventually CM Punk gets a bodyguard (Unsure who that could be) and he injures Batista. Just a couple weeks before Mania, the bodyguard is: 1) Banned from ringside at WrestleMania and 2) Not allowed, along with CM Punk, to lay a hand on Batista or Punk will forfeit the title and will not compete at Mania. Then, at Mania Batista and Punk have Punk with most control well focused on Batista's "Injured neck". However, Batista begins to fight back. But, when going for a spear Punk avoids it and 'Tista hits his head in the corner. Punk rolls him up and gets the pinfall around 15-20 minutes in.
Randy Orton vs Ted DiBiase vs Cody Rhodes
At No Way Out/Elimination Chamber, Randy Orton demanded Ted and Cody to help in his match against Triple H so he can win the title back. As Legacy is ringside, Cody is about to interfere but Ted isn't going to. So, Cody doesn't. Randy gets pissed and yells at Ted from in the ring, and once he turns is hit with the pedigree and is defeated. Post-match Cody checks on Randy well Ted is in the corner. Once Randy is back up, he pushes Cody away and gets in Ted's face. He starts to yell at him, and slaps him across the face. This causes the two to begin to brawl. However, Randy misses a clothesline on Ted and accidentally hits Cody. Ted hits his finisher and walks out. This leads in the upcoming weeks Randy beginning to get angry with Cody as well because he won't help him in his beatdowns of Ted. In one match, its Cody and Randy vs Ted in a handicap match, but once Cody doesn't listen to Randy, he is RKO'd. This causes an altercation between all three, and it later leads to a triple threat match being set up for Mania. In the match, Orton has control at the start, then it transitions between Cody and Ted. Orton is double teamed, up until Cody turns his attention to Ted. Randy hits an RKO out of nowhere on Cody, but Ted gets the Dream Street on Randy and wins the match around 20 minutes.
Undertaker vs Mr. McMahon
At TLC, Undertaker loses the World title in a TLC Match to CM Punk. At Royal Rumble, Taker is in a match attempting to regain the title, and once again Scott Armstrong is the referee. During the match, Punk knocks Taker out of the ring, and Scott begins to count (slightly fast) as Taker is starting to get back up, Vince is coming down to the ring. As Taker reaches his feet and Scott is up to an 8 count, Vince hits Taker from behind. However, Scott doesn't call a disqualification and finishes the count. As Punk walks out with Vince Taker is sitting up pissed off. He gets back in the ring and chokeslams Scott. This leads on Smackdown, Vince telling Teddy Long to suspend the Undertaker. Teddy does. With 3 weeks before Mania, Kane (turning face) goes into Teddy's office and grabs him by the throat. He tells him he has a message from Taker and that's he demands to have his suspension lifted and to face Vince at Mania, or both of them will forever Rest in Peace. Teddy listens, and later that night announces it. Vince is about to overthrow it when Kane comes down to the ring and chokeslams him. The next week, Vince says that Kane has been suspended and he will not face Taker at Wrestle Mania. However, the lights go out and Taker appears in ring when they are back on. He grabs Vince by the throat and lifts him up high. He says something to him, and chokeslams him down. This leads on with Vince accepting the match, and if Taker loses he is out of the WWE for good. At Mania, Taker dominates the match completely with Vince getting a few cheap shots here and there, but eventually Taker finishes him off with a tombstone in the middle of the ring around 10 minutes and wins.
United States Championship
The Miz(c) vs John Cena
Basically in this feud, Miz starts stuff up with Cena again, and saying that now Miz is a champion and Cena is still a loser. This brings Cena out, and says if Miz is so confident, he can put that title on the line at Mania against Cena. Basically a squash match, as Cena wins with the Attitude Adjustment in just under 3 minutes.
Unified Tag Team Championship
Chris Jericho and Big Show(c) vs Edge and Christian
At the Royal Rumble, Edge returns and eliminates both Jericho and Show. As recently Christian has been taken out of the ECW Title picture and is just fading out and was eliminated earlier on in the Rumble match. After Edge doesn't win the rumble, he is beat down in the following weeks by Jericho and Show. However, Edge manages to beat them both in singles matches, but loses a handicap match. This has Edge challenge them to a match at WrestleMania for the Unified Tag Titles, and his partner is revealed the next week to be Christian, who is set up to face Big Show that night, and eventually finds a way to win. At Mania, in a pretty good match, Edge manages to hit a spear on Show, not knocking him down but enough to get him dazed, and Christian with a Killswitch and the team getting the win in about 9 minutes.
Non-Title Champion vs Champion Lumberjack Match
Diva's Champion Melina vs Women's Champion Beth Phoenix
Basically, brand supremacy between the Diva's. Melina gets attacked a lot in the match by the lumberjills but eventually manages to hit her finisher on Beth and get the pinfall.
Money In The Bank Ladder Match
John Morrison vs Rey Mysterio vs Dolph Ziggler vs Sheamus vs Shelton Benjamin vs MVP vs Jack Swagger vs Evan Bourne
To determine who's in the match...
Raw 1st week: MVP defeats Chavo Guerrero
ECW 1st week: Sheamus defeats Goldust
SD 1st week: Dolph Ziggler defeats Finlay
Raw 2nd week: Evan Bourne defeats Chris Masters
SD 2nd week: Rey Mysterio defeats Eric Escobar
Raw 3rd week: Jack Swagger defeats Primo
ECW 2nd week: Shelton Benjamin wins a 8 man battle royal also featuring William Regal, Ezekial Jackson, Paul Burchill, Hurricane, Tyler Reks, Yoshi Tatsu, and DJ Gabriel.
SD 3rd week: John Morrison defeats Charlie Haas
The match features a lot of high spots as most of these guys are high flyers. The match comes to an end as Morrison delivers a Moonlight Drive off the ladder on Swagger, and Ziggler takes advantage with everybody down and takes the briefcase.
Extreme Rules Match for the ECW Championship
Zack Ryder(c) vs Tommy Dreamer
Basically, Zack Ryder is giving disrespect towards Dreamer, and insults him saying he is the only original ECW star, and he is officially an outsider. He doesn't deserve to be a part of ECW anymore. Dreamer steps up to him and says that if he thinks he's such a joke, he should face him in an extreme rules match. Claiming he is the true best and he can do anything (Woo Woo Woo, You Know It!). The match has some good spots in it including Dreamer throwing Zack through a table from inside the ring to the outside. The match ends when Ryder hits a Zack Attack (The leg lariat thing) on a sitting steel chair and gets the pin.
There's my Mania.