The Edge & Cena feud will forever stick out in my mind as one that helped catapult both guys to another level. It helped Edge become a big time main eventer (although he kinda already made it to that level during his mini-feud w/ HBK), and it gave Cena his "balls" back because this was around the time when people were calling him a cartoon character. All of their matches had the drama, a great story, and Lita...it was the hottest thing in 2006. Edge & Foley feuded and made headlines with their WM 22 match, but it was all a part of the Cena/Edge story because remember, it started with Foley counting Edge down to reward Cena his belt again. Same with Cena/Triple H (and RVD), who many thought was going to engage in a long rivalry, but again, the focus was on Edge/Cena. Just want to point out that this was before the return of PG programming, so it made for a great reality show.
Not to be making this about Cena, but the point I'm making is that not even the great almighty Triple H could do for Cena that Edge did. It couldn't have come at a better time. From January-September 2006, it was a great time to be a WWE fan.