The problem with the SMT series is that if you're expecting the other games to be similar to the Persona games, you'll probably end up being disappointed. The mainline games in particular have a more restrained approach to narrative as it's very gameplay-first. You can go hours without any cutscenes. Just thought I'd throw that out there.
As for me, probably the Etrian Odyssey series. I've been meaning to try one of the games for a long time now, but dungeon crawlers have never been my thing. Also, the Legend of Heroes series is another one. Particularly, the Trails in the Sky and Cold Steel games. Everybody sings their praises about how great the story and characters are. I still have memories of playing the generic Legend of Heroes games early on in the PSP's lifespan, which is why I probably haven't had much interest in playing the current games.