An rpg would take my personal spot for that.. but hard to point one specific out. I'll at least break it down to 3 honorable mentions.
Final Fantasy VIII- First rpg ever, and my favorite of the ff series, in which contains many honorable rpgs of my childhood already. I can't even look at the title without feeling nostalgia, even if it's very easy after breaking myself into more advanced jrpgs. I could just put the entire FF series as a stander for this, but VIII holds a special place in my heart that leaves me helpless to pointing it out on this list.
Mana Khemia 2: Fall of Alchemy- Love it, awesome music, comedy, 2 entire different parties to play as (and the satisfaction of mixing them both together after completing both stories), addicting battle and crafting systems, and cute and likable character designs. Overall one of my favorite rpg experiences I ever had, though the game was a pain to find.
Disgaea 4: A Promise Unforgotten- The only Disgaea game I've played so far, however it's enough to show me how awesome this series is. I've had this game for maybe 2-3 years, and I'm still unlocking features and new content to date whenever I pick it up (Even with a lvl 9999 char.) The plot alone was fun and satisfying, so even those that don't care for it's amazing end-game can still find an enjoyable experience. The strategy battle system was fun and smooth. And with the many ways the characters can be built or created, it leaves many ways to experience through the game for each player. The overall soundtrack is also amazing, and becomes more enjoyable if you unlock the music shop in Item World! The designs are attractive and entertaining to go with the plot just as far-fetched. I would be exploring the whole series, but Disgaea 4 is still stealing me hours of content to play, and I'd feel overwhelmed with any other titles for now. xD