Started with Moldvay/Mentzer D&D and branched out from there pretty early. Nowadays, my group has played multi-session games of D&D, Blades in the Dark, FFG's Star Wars, Deadlines (via Savage Worlds), and one-shots of even more systems.
I started playing 2e with my father and some family friends, then 3rd edition. When I got out of high school, I met a few of the people that are now in my current D&D group and we played 4th edition. I continued playing 4e until the official builder went offline and the group has transitioned to 5th edition and have played that ever since. I've never tried any other TTRPG system, though a few have been recommended by some of my friends.
Started to play in 1980 with D&D my DM had the white box and we switched to AD&D a year later. Got my Moldvay box at 12 and stared to DM right there and through all editions.
But I have played:" Star Frontier, Star Wars WEG, Call of Cthulhu, Black Eye, Vampire the Masquerade, Werewolf the Apocalypse, Heroes, Marvel, Palladium games ( Fantasy, Rifts, Supernatural, Robotech, Nightspawn and a few others), GURPS, Role Master, Space Master, Paranoia, Warhammer and a fee one shot tries I don't even remember their names. I do have the Battletech RPG and the technical readouts but never acually played... So yeah, I did play a lot and still play a lot.
When I started there wasn't much choice. I started with Holmes box set, then moved to AD&D when the players handbook was published a few months later. I've played, and enjoyed 1st, 3rd and 5th. My primary game in HERO/Champions, and I play Modern Age, Genesys and Cypher and some Pathfinder 1st ed. We tend towards heavier/crunchier systems, so 5E is a "popcorn" game that my wife and I do solo.
I think the first TTRPG I played was actually Judge Dredd? D&D 2e was almost my first, but not quite, and I didn't become heavily invested in D&D until 3/3.5e. I've tried lots of systems since then, but D&D 4e is my forever girl. (I really wanted to love Exalted, but it just didn't work out; I needed someone more mechanically reliable.)
The next most popular thing my group enjoys these days is a bit of Blades in the Dark, and related variants.