Given what Death said, but remembering that this is all in the spirit of fun:
The Streak. Both world championships have lost prestige years ago, and have been passed around like candy this year. They have also been put around the waists of some questionable champions. Whilst The Streak has The Undertaker taking on the best of the best in the company, and it has been going on for longer than anything else in the WWE. There will be no one who will even come close to touching The Streak, even after Taker retires.