There's too many great ones to list them all, but two of my favorites is Austin/McMahon and Austin/Bret. No coincidence that they both contain my favorite of all time, Austin. Austin/Vince is an obvious choice. Austin/Bret was also magical. Austin was the perfect enemy for Bret, not to mention the awesome double turn at WM13 and Bret's heel turn the next night that had some reality to it. And say what you will about Bret never drawing, but Raw's ratings went up in the summer of 1997 when Bret won the belt. I know Austin was getting bigger but Bret and the Hart Foundation angle was a hot angle and I think contributed, especially since Austin got injured around this time.
If we count WCW, then the NWO storyline, of course. Not to nitpick it or anything, but it no doubt got bloated overtime, but up until March/April 1997, it was perfectly booked for the most part. Things started to annoy me little by little after that.