#1 Sheamus vs Daniel Bryan

This match has happened twice at WrestleMania, including a pre-show match that turned into a Battle Royal. Daniel Bryan and Sheamus were even scheduled to face each other at WrestleMania XXX before WWE mercifully relented to the fans and inserted Bryan into the WWE Championship picture. This time around, it is a genuine possibility.
Daniel Bryan is currently wrapped up with "The Fiend" Bray Wyatt and the Universal Championship, with the blowoff match likely for Royal Rumble. After that, Bryan's WrestleMania prospects are an open book. Meanwhile, Sheamus is on the cusp of returning and has threatened to take over Friday Night SmackDown. He even has his old hair back.
This is a high profile match of sorts, especially if there are some stakes added to it. After finishing off with The Fiend, Bryan could win the Intercontinental Championship from Shinsuke Nakamura and then defend it against the Celtic Warrior at WrestleMania. It is guaranteed to be a great match, provided they get more than 18 seconds.
Also, throw in the fact that the IC Title is the only one left for Sheamus to win in WWE and it makes for a very interesting scenario. Out of all the possibilities WWE could choose, this may be one of the better Intercontinental title matches for the 'Grandest Stage Of Them All'.