Okay, off the top of my head, favourite feuds would be:
Samoa Joe vs. AJ Styles vs. Christopher Daniels - Great 3 way feud that made all three look great coming out of it. Fantastic matches every other week.
LAX vs. The Phenomenal Angels - AKA how to get a new tag team over instantly.
Bobby Roode vs. James Storm - Great revenge story, with Roode repeatedly fucking over Storm until he got his comeuppance in a bloody, violent feud ender at the biggest show off the year. Loved it.
Kurt Angle vs. Desmond Wolfe - Already mentioned, but rightly so. McGuinness walks straight into TNA and within a month is made to be seen as on Kurt's level. And the best thing is that Kurt never actually lost any of their matches, proving that you can make someone look good in defeat if booked right.