I am a bit of a system tart, always attracted by the new. And of course my current favourite, Coriolis, isn’t that old. So what games, even if not my favourite, have stayed with me. Traveller is like a comfortable old shirt. I can just slip it on, pull a character together, and slip into the Imperium, even though I have not played it for years now. I can play with anyone. I think the current integration (2nd Edition Mongoose, not T5) is the perfect distillation of decades of rulesets.
Pendragon is a game that I have played a single campaign of, for over 30, getting on for 40 years. I love it’s generational scope. RuneQuest or rather Glorantha is a world that inspired me 40 years ago, but I only got to experience it properly recently.
But my true love is Coriolis and I guess it stays with me because about five years ago, I started a podcast about it. I am kind of committed.