The first IC champion I remember was Randy Savage (although I might have started watching right before he won it from Santana). He had a great heel run, then you had Steamboat as a transitional champ and then HTM's long ass reign. Warrior and Rude were both legit. Von Erich had a short reign. Perfect was great as champion. Bret was great, and his win over Perfect was one of my favorite matches. His feud with Piper was fun, and the Bulldog match was excellent. Then HBK got his first singles title. All that was legit.
This was around when I took my first break from wrestling, so I missed Diesel's run and a good chunk of Razor's, although I think he had the title when I first came back and then Goldust won it. That reminded me of HTM's title reign, with the hated heel as the long-time champion. I think Ahmed beat him, but then I don't remember what happened - maybe dropped it to Farooq? Before long you had HHH, Rocky, Austin and Owen all as IC champions.
I'm having trouble remembering who came next, but it might have been in that next group of guys that the title lost some prestige. There were also more titles with the European title and Hardcore title, even before they bought WCW and brought in the US title.
I remember a really young Randy Orton feuding with a pretty young Edge for the title right before I took my second wrestling break. They were at least trying to to make it matter still at that point.