Triple H/Taker is definitely gonna be second last, unless they decide to stick a woman's match in between that and Rock/Cena. They sometimes put the least important match second last because if the PPV starts to run a little long, they will always take time from that match in order to preserve more time for the main event.
Sheamus/Bryan will probably be the opening match of the card, just like Edge/Del Rio was last year. (Ironically, Sheamus/Bryan was bumped from the show last year and made into a dark match.)