1- Edge vs Cena
It was probably the most natural feud John had, I would say this was the feud that launched both of these men's career, Rated R Supertar vs Clean Superface of WWE, Even Cena would tell you he learned the most from his feud with Edge and it was Edge who helped him grow as main eventer. That feud was the best feud of the 2005-2010, we had the MITB cash in, biker Edge spearing Cena at ONS06 helping RVD win, Edge winning the title, slapping Cena's father, beating him in his hometown, Cena returning the favor and putting Edge trough two tables in a TLC match, Cena FU-ing Lita IDK how many times, Cena throwing Edge in long island sea, and then they fought in a cage match to end the feud ( but they didn't end did they? DX interference..)
and they were kind enough to renew the feud in 2009 and give us one of the best Last Man Standing matches by far..
2- Sting vs Jeff Jarrett, another feud that started at the beginning of 2006 and didn't end till nearly 10 month later, Sting was honestly the first face to come TNA that was probably a bigger draw and name than Jarrett , he helped Christian in his feud with him, there was really a lot of brawling and screwing each-other around in that feud, and it had to end at the biggest stage in TNA, BFG, Where it Sting vs Jeff career vs title..
3- Shawn Michaels vs Triple H 2002-2004 (Man I really hated every-time Triple H beat him back then..)
4- Undertaker vs Edge, this feud lasted for nearly a year a half, I'd say from cashing in the MITB in 07 till next year's Summerslam 08, what an epic feud...
First of all they had an amazing chemistry in the ring, the match at WM24 is in my opinion the most underrated WM match of all times, it was fantastic! The HIAC match is also easily a top 3 best HIAC matches ever( and I can make a case for it being #1...if only it wasn't PG, but they proved you don't need blood to make a ***** HIAC match, which is an excuse for why the HIAC PPV sucks)..anw, Edge cashing in on Taker, costing him the title at SurvivorSeries07, winning the title by getting doubles, feuding with him leading to WM where he was undefeated in 1 on 1 matches ( and at the time I tough he had the best chance of beating Taker, Taker's DVD of 15-0 had just came out, so I tough they did the DVD, Edge could win now..), and with Vickie by Edge's side she made sure Taker got to rest, she banned his choke hold, vacated his title..ect and Banished Undertaker when he lost the TLC match, only to get him back to finish off Edge in that awesome HIAC match.
5- ( probably not my 5th favorite, but it is my favorite mid-card feud of all time, so I decided to put it) MVP vs Matt Hardy.
They had great matches for the US title, and a great feud that lasted for a while, they were as sure as hell outshining Khali in summer of 07 on smackdown.