The Legend of Zelda: The Minish Cap for Game Boy Advance
The Legend of Zelda: The Minish Cap is great! I was a wary for a while because Capcom made it rather than Nintendo, but once I got my hands on it, my fears were quickly diminished. This is a Zelda game in every sense of the word. You have a top-down action adventure with an overworld, you have dungeons to defeat, various monsters to fight and items & treasures to discover, and plenty of side quests & side games to keep you coming back for more. The added "mini" puzzles and Kinstone secrets fleshed out the game much more than the basic travelling from dungeon to dungeon.
I personally have a real soft-spot for Legend of Zelda: A Link to the Past for SNES, so that will always be the #1 Zelda game for me. But right after that, I would place Legend of Zelda: The Minish Cap. And that took the original Legend of Zelda's (for NES) place in my personal ranking of Zelda games.