Legend of Mana for the Playstation 1.
I know it's the black sheep of the Mana series, and I'll say up front that game is FAR from perfect, but it's the closest I've ever come to a perfect game, especially when my overall biggest complaint is that I wish there was just more of it.
The game is gorgeous, despite being a PS1 game it uses an artwork style presentation that still holds up to certain games made today. The world and characters are vast and interesting, and the levels of customization available in spells, armor, weapons, golems, and monsters is staggering.
It does a good job of blending serious story with an air of comedy, it's got pretty fun co-op options, and a lot of neat options for replay value.
To me the most noteworthy thing is I've beaten the game over 100 times, and I'm still discovering new things, however small. You never know what mixing up the order you do certain quests in or having along a certain NPC at a certain time might add to the dialogue.
And don't even get me started on the soundtrack <3
Yeah it has its flaws, combat can be a little repetitive, the same monsters always being in the same places can make it repetitive, but I really feel like the flaws it has can be overlooked with how amazing the rest of the game is.
I still just play through it every now and then for the fun, and I can't say that about a lot of games out there.
No doubt about it, Legend of Mana is my absolute favorite.