Though we played a lot of fantasy games (mostly AD&D) in my middle and high school years--probably more than anything else--our longest campaigns (defined as the same characters in the same setting/situation) were in superhero games. While we'd played with Villains & Vigilantes and with the first editions of TSR's Marvel Super Heroes and Mayfair's DC Heroes, our "Heroic Age" really got started in '86 after the release of the Marvel Super Heroes Advanced Set.
Our first and longest running team was called the New Champions (taking the name from the L.A. based team of the Bronze Age and the idea of a new iteration from The New Defenders, which had just ended the year before). Our characters were street-level/near street-level characters, some of which were reformed villains. We picked the characters from the pages of the Official Handbook of the Marvel Universe, for the most part, rather than going with well-known characters. I used Paladin, my brother, Puma, and our friend Al, Hobgoblin (the former Jack o' Lantern version). That was the core group of players and characters, but other players and other Bronze and early Modern C-listers joined the New Champions ranks at some point: White Tiger, Madcap, Shroud, and Unicorn, among others I've likely forgotten. The team had a West Coast era (borrowing from West Coast Avengers, which I had a subscription to), as well, and probably at least one "all-new, all different" period--but it was also part of the same continuity.
The second edition of DC Heroes, was probably our last gasp of superhero gaming. The Marvel games had mostly been over the summer and with a crew somewhat different than my usual gaming group, since none of us were able to drive yet and it was tough to get together when we weren't in school. By '89 though, that wasn't the case, so the DC group was largely the same as my Dungeons & Dragons and GURPS crowd. This time, we made up our own characters and our own super-hero universe. Lower key, more "realistic" superheroes were the order of the day. About half of the group (which was never named as a team, really) didn't wear costumes, and the villains were are somewhat quirky, and many of them didn't wear costumes either. I suspect the primary inspiration was the Wild Cards universe, but Thriller, the New Universe, and Doom Patrol might have been in there, too.
We played some 4th edition Champions after that and maybe some GURPS Supers, but neither of them had the ease of use of MSHRPG or DCH so they didn't last long. These two campaigns created some truly memorable characters--or at least memorable sessions.