I don't remember a lot of my early comics, but, like most people, it would have mostly been superhero stuff. I remember one of my favorite comics was an early Spider-Man (#141) which had a story where Mysterio convinced Spider-Man that every single one of his villains were attacking him at the same time. It was my favorite story, and such an intense issue. I think I identified with his feelings of being battered from all angles.
I also had that oversized Battlestar Galactica Marvel Super Special. “In full Marvelcolor,” whatever the hell that is! I remember loving that thing so much. I wish I still had that. I’m sure part of the reason was its size. It was huge! On my last trip to St. Louis, I dug out the first 4 issues of the '80s Marvel BSG series that I picked up somewhere along the way, and read them, but they sucked. Very dated, especially compared to the new TV series (which is outstanding).
I know I also had a ton of Star Wars comics, but I especially remember the mid-series Marvel run adapting The Empire Strikes Back. I read those issues dozens of times, and I remember my dad got me some trace paper and I spent hours tracing that Boba Fett cover on issue 42.
I also remember an issue of Detective Comics (#367) with Batman fighting Jigsaw, and along the bottom of the cover was an actual jigsaw puzzle. I was so young, I actually cut off the bottom and carefully cut out all the pieces. Still one of my favorite covers of all time.
I also remember I had this large plastic die-cut Superman American Greeting Cards display thing. It was huge, like 4 feet wide, and puffed outward in 3D. I think it was from a greeting cards display my dad had in his old pharmacy before it burned down. But somehow, this thing survived. Actually, I think its still somewhere in my parents' basement right now, but now there's so much crap down there you can barely walk around.