I whole heartedly agree on Jericho vs. Goldberg. I don't see what Bill was so threatened about, Jericho had stated he'd glady let himself be obliderated in squash like fashion, because basically fans have wanted to see that for months. It was a perfect element really, because fans who hated Jericho (obviously acknowledging he had a following as well), wanted to see him get his come uppance not just during the Goldberg feud, but for the entire DAMN year! He always found ways to win, and whenever he did loose, he was never down for long, finding loopholes, or winning another title soon after. The fans who hated Jericho from a mark standpoint, wanted to see him get the living PISS beat out of him for a year! Who better to do that than the biggest star in the company (this would be the part where Hogan would interrupt my post saying "I never feuded with Jericho in WCW"!).
Another feud would be Austin vs. Regal. This is arguable yes, but IMO, I just think these two would've meshed well. Austin was always good at working with technicians. And the feud could've played out with Regal, getting sick of the fact that the WWF wasn't being represented with class and good manner, and claiming he could be the guy, there could've been some great comedic segments between the two of them, with vignettes of Regal teaching a few Austin fans to be gentlemen. And then Regal just gets downright nasty with a vicious beatdown, and becomes royally obsessed with his mission.
Another one that's a bit more recent, is Shawn Michaels vs. Shelton Benjamin. After there showdown on "Raw" back in '05, and when Shelton turned heel later on, he and Shawn were having a few verbal altercations backstage, about Shelton's overall attitude and ablities etc. And I thought it could've lead to something.
One from 1990 or '91 WCW, is Ric Flair vs. Scott Steiner, I know they had a bit of a feud, and a big match, but I really think they didn't go all the way with it, and had the chance to make it seem significant, Scott was really catching fire as a singles star, but the match was so bad (and it was from what I recall), that Scott's push was derailed.
But NUMBER ONE...always for me....Bret vs. The Old Guard! See here's the thing, now I know that this is just me playing fantasy booker. I always envisioned Bret's babyface push, phasing out the old guard. Him vs. Warrior would've been great at Wrestlemania IX, as would've him and Hogan at Summerslam '93. I always thought Savage should've gotten one last push, and many have said that. No disprespect to Mr. Backlund, but it would've been great, having Savage play the psychotic ex-champ with a chip on his shoulder, and a heel turn wouldn't hurt him, he always had a huge following regardless of what side of the fence he was on.