I don't see why Wrestlemania even needs a million different themes. Wrestlemania 25 had about three or four. I remember them playing "Thunderstruck" by AC/DC at one point, then "Be Yourself" by Audioslave. There was one other at least.
"Written In The Stars" is the only theme they need for Wrestlemania 27, it fits the PPV perfectly. Though, I thought I heard them play "Hangman" by Rev Theory when they showed the still photo for the Undertaker vs. HHH match last week on RAW.