That list doesn't even make any sense. First off, you're considering a Main Event match to solely be the last match on the card. A Main Event can be placed in the middle of the card as long as it's still treated like a huge attraction. All of Edge's PPV matches and all of Cena's PPV matches have been given that attention since WrestleMania so I'm changing your criteria. Furthermore, Edge has only been in one final match Main Event from WrestleMania to One Night Stand, so of course he's going to have a difficult time comparing to Cena. If you consider Edge a Main Eventer and Cena a Main Eventer, it would make a lot more sense to simply look at their matches separately, no matter where they placed on the card. And, just for argument's sake, I'm throwing in Vengeance as well.
Cena
vs. HHH at WrestleMania XXII
vs. HHH vs. Edge at Backlash
vs. Rob Van Dam at One Night Stand
vs. Sabu at Vengeance
Edge
vs. Foley at WrestleMania XXII
vs. HHH vs. Cena at Backlash
with Mick Foley vs. Tommy Dreamer and Terry Funk at One Night Stand
vs. Rob Van Dam at Vengeance
Personally, I think Edge has had the better match at WrestleMania against Foley, One Night Stand in the tag match, AND Vengeance against RVD when compared to the respective matches Cena fought in. In fact, he has consistently proven himself as perhaps the best all-around Main Eventer in WWE in 2006. Besides Pay-Per-Views, just find me any Cena match from a 2006 episode of Raw that comes close to competing with the Edge/Flair TLC match from Raw back in January. He doesn't compare to Edge's efforts this year.