Here's the games I played in the 80's and early 90's. I was just thinking about this stuff lately, guess I'm getting nostalgic.
Marvel Super Heroes - Played a few games. It was fun, but not a major campaign.
Moldvay B/X plus Mentzer Companion set - This was my go-to game for the first few years I played.
AD&D 1e - Played for a couple years.
AD&D 2e - Played a LOT. Vastly prefer the 2e thief to the 1e version.
MERP - Loved this game. We played this one a lot.
Star Frontiers - This was the generic sf game we played. Just a couple one-shots. We liked fantasy more.
Rifts - Several major campaigns of this. Loved the setting, and liked the rules. I had a Ley Line Walker that could just destroy stuff.
Twilight 2000 - We played this a few months while I was in the Navy. It was a lot of fun.
Settings we used:
Forgotten Realms 1e box set. We had a Wild West style fantasy game going for several years in between Rifts adventures.
A Middle Earth/Shadow World conglomeration. We used modules from both settings (though the game was nominally in Middle Earth).
The Known World. I got a LOT of milage out of X1.
Starship Troopers style game with the Star Frontiers rules.
Rifts North America. We wandered around causing all kinds of havoc. It was a blast.
Post-apocalyptic Poland and then Pennsylvania. We actually had the setting book for where I grew up in Bedford. It was kind of funny, and not so accurate.