I got into the Megami Tensei franchise with a six-month run of a bunch of the games and it's still something I think about pretty much all the time. I bought Persona 2: Innocent Sin years ago out of curiosity, then Nocturne caught my eye, then Persona 4 real-time commentaries had me excited for that, then I played Strange Journey alongside two other people, and so on.
Nocturne, Digital Devil Saga 1+2, and Strange Journey are my favorites, I think.